Fiberoptic-guided interstitial seed manual applicator and seed cartridge

ABSTRACT

A method for implanting seeds in or about a target area, such as a tumor, within a patient. The implantation device includes an implantation needle having a bore extending longitudinally therethrough from a proximal end to a distal end of the needle, the needle bore being adapted to permit at least one seed to pass therethrough. An elongated plunger extends longitudinally through the implantation device in aligned relation to the needle bore. An optical device is carried by and operatively connected to the plunger to provide visual assistance to an operator of the implantation device to guide and verify implantation of the ejected seed into the target area.

This application is a Division of Ser. No. 08/763,759, which was filedDec. 11, 1996. U.S. Pat. No. 6,102,844 Aug. 15, 2000.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates generally to the field of medicalimplantation devices and, more particularly, to an improvedfiberoptic-guided interstitial seed manual applicator and seedcartridge.

2. Description of the Related Art

Afterloading brachytherapy has been in use since 1960 when it waspioneered in the United States by Ulrich Henschke. In this medicalprocedure, malignant tumors and the like are treated by surgicallyimplanting radioactive sources (“seeds”) in or about the malignant tumorin order to irradiate the malignancy. The term “seed” as used herein isintended to broadly mean an object or body to be implanted within apatient, including, but not limited to radioactive seeds used inbrachytherapy procedures.

A variety of different radioactive materials have been used as seeds.For instance, Basil Hilaris was the first to use Iodine-125 forpermanent implantation in a tumor. Since then, use of Iodine-125 haspersisted, serving as the seeds used in the vast majority ofinterstitial brachytherapy implants for a host of tissues and organs.More recently, Palladium-103 has been approved for use as an implantableradionuclide and applications using Palladium-103 continue to beexplored. Other radioactive materials that have also been used includeRadon-222, Gold-198 and Iridium-192.

Precise location and spacing of the implanted seeds is of particularimportance in the treatment of such malignant tumors and the like. Poorlocation or distribution of seeds can result in undesirableconcentrations of seeds leading to either an overdosage or underdosageof radiation. As such conventional interstitial seed implantation isfrequently performed through an open surgical incision in the patient.In one conventional technique, hollow needles are inserted into thetumor and the seeds are thereafter placed in the needles while theneedles are being retracted to implant or deposit the seeds in thetumor. Popular instruments commonly used today for surgically implantingseeds in or about the tumor include the Henschke, Fletcher-Suit, andMick applicators, Royal Marsden gold grain gun, and stainless steelneedles/hairpins. With few exceptions, however, the basic concept anddesign behind most of these seed implantation systems have changedlittle over the years.

In contrast, the last two decades have witnessed remarkable advances insurgical, imaging, and anesthetic practices, as well as new developmentsin permanent radionuclide source availability. Despite the fact thatmany surgical procedures are currently accomplished using conventionalendoscopes or laparoscopes with minimal or limited incisions into chest,abdominal or pelvic wall tissue, conventional implantation systems havegenerally failed to combine such a technique with brachytherapyimplantation due to a dearth in brachytherapy technology.

While many problems associated with interstitial seed implantation havebeen addressed by the above-mentioned conventional implantationinstruments, there remains a tremendous need to develop an interstitialseed manual applicator that utilizes fiberoptics and is capable ofprecise implantation of seeds using minimal or limited incisions intochest, abdominal, or pelvic wall tissue of a patient.

In addition, seed handling in connection with brachytherapy has notchanged since the inception of this therapeutic approach thirty yearsage. Seeds may be ordered from a distributor and typically arrive loosein a protective lead-lined pig. Seed strength and number of seeds aregenerally communicated on the appropriate paperwork accompanying theseeds. Following delivery of the seeds, however, all further seedhandling duties are typically accomplished manually by the radiationoncologist or related technical staff. These duties include seedcounting; loading seeds into the appropriate cartridge, needle, ormagazine; sterilizing the seeds in their receptacle for use in theoperating suite; keeping a running tally of the number of dispensedseeds in the operating room with paper and pencil; surveying of theoperating suite following the procedure in order to track possible looseor stray seeds; and frequent switching of empty seed cartridges,needles, and magazine due to limited seed capacity.

Not only is this current seed handling procedure labor-intensive, but itinvariably leads to radiation exposure of the personnel involved. In thebest of circumstances, seeds can jam or dislodge from their receptacleand become temporarily or permanently misplaced. Sterilization of seedsintraoperatively wastes precious time and maintaining an accurate seedtally can be confusing. Accordingly, there is a tremendous need todevelop a device that simplifies seed handling in connection withbrachytherapy and minimizes the above-mentioned problems associated withcurrent techniques.

SUMMARY OF THE INVENTION

By the use of the present invention, it is no longer necessary to limitbrachytherapy applications or other implantation procedures to instancesinvolving large, open surgical wounds or incisions. Rather, seedimplantation may be achieved with fiberoptic or other optical assistancethrough a small incision associated most commonly withminimally-invasive surgery, as well as with the traditional large, opensurgical incision. In addition, the fiberoptic or other opticalassistance provided in accordance with the present invention facilitatesaccurate seed implantation into the target tissue using directvisualization of the seed passing into the tissue. Such an advance inseed implantation technology as a result of the present invention willbroaden the applicability of interstitial implantation to include thosepatients who undergo fiberoptic-guided tumor biopsy and ordinarily wouldbe sent for external beam radiotherapy thereafter; patients whomedically cannot tolerate a large incisional wound; patients who arepoor operative candidates based on technical considerations, such asthose who have been previously irradiated with external beam therapy andwhose tissues would heal poorly with additionally radical surgery;patients with recurrences following either surgery or radiation therapy;or patients in whom minimally-invasive interstitial implantation isdeemed advantageous. The unique features of the implantation techniqueand manual applicator according to the present invention, including itsfiberoptic guidance, minimally-invasive surgical requirement, automaticfiring mechanism, gravity-independent posture, and integraldispenses/remaining seed visual indicator all serve to enhance theattractiveness and utility of interstitial brachytherapy, in general,and of this novel system in particular.

The foregoing and other objects and advantages are achieved inaccordance with the present invention through the provision of afiberoptic-guided interstitial seed manual applicator (FOGISMA) orimplantation device. According to the present invention, a method andsystem is provided for interstitial implantation into or aroundneoplasms of tumoricidal or tumoristatic doses of radiation carried byradioactive seeds whose placement is guided via an intrinsic fiberopticor optical component, potentially, but not necessarily, enhanced bylaparoscopic, thoracoscopic, bronchoscopic, cyctoscopic, or other typesof assisted surveillance including direct vision. The FOGISMA deviceaccording to the present invention may require minimally invasivesurgery in order to introduce the applicator through a smallincisioninto the target tissue, rather than the wide open incision required byprevious techniques.

With proper mounting, the FOGISMA device according to the presentinvention may also be used for percutaneous seed implantation, such asthrough the transperineal route for implanting the prostate gland. Thesame automatic firing mechanism and precision needle positioning as withthe minimally invasive technique would apply, with the advantage ofknowing the exact location of the needle tip by fiber optic guidance.The radioactive seeds are introduced one at a time from a shielded seedmagazine down the a barrel of the applicator into the target tissueusing a gravity-independent automatic firing mechanism instead of theconventional manual plunger, and the introducing needle is automaticallywithdrawn the desired amount by the precision FOGISMA device. Seeds maybe placed sequentially along a given needle track and/or in separateneedle tracks, while maintaining an integral visual numerical indicationof all dispensed/remaining seeds.

In accordance with the present invention, an implantation device isprovided for implanting seeds within or adjacent to a target area, suchas a tumor, located within a patient. The implantation device comprisesan implantation needle having a bore extending longitudinallytherethrough from a proximal end to a distal end of the needle. Theneedle bore is adapted to permit at least one seed to pass therethroughinto the target area. An elongated plunger extends longitudinallythrough the implantation device in aligned relation to the needle boreand is selectively movable in the longitudinal direction relative theneedle from a retracted position spaced apart from the needle to anextended position wherein the plunger is advanced through the needlebore to eject at least one of the seeds through the bore, out of thedistal end of needle and into the target area. An optical device iscarried by and operatively connected to the plunger to provide visualassistance to an operator of the implantation device to guide and verifyimplantation of the ejected seed into the target area.

The FOGISMA implantation device of the present invention may alsocomprise: (1) a multi-seed cartridge, either pre-packaged or loaded adhoc, which is inserted into the proximal end of the device; (2) anoperational/controlling proximal end with a grip that allows the user,manually or with robotic assistance, to adjust and guide each motionrelated to seed placement; (3) a rotating loading barrel in the midportion of the device that assures precise transfer of each individualseed from the loading chamber into the firing chamber; (4) an introducerneedle attached to the distal portion of the device that is effectivelyexposed from a protective sheath, enabling the needle to be driven intoor around the tumor, thus providing a channel for seed insertion; (5) anouter sheath that functions as a protective housing for the introducerneedle in its resting position and is adjustable to appropriate shorterlengths as required to permit a given length of the introducer needle toprotrude for desired tissue penetration. Upon firing a radioactive seedinto tissue, the subsequent seed in the seed cartridge willautomatically shift into firing position, permitting easy and rapidfiring of any number of seeds deemed appropriate. Additional seedcartridges may be required and can be exchanged for exhausted cartridgesas necessary.

The present invention further addresses the glaring shortcomings ofconventional seed handling in a way that will facilitate the use of thetherapeutic modality by both seasoned practitioners and those who havebeen reluctant to attempt it in the past because of it inherentdisadvantages. A Brachytherapy Interstitial Seed Cartridge (BISC) isprovided in accordance with the present invention to hold a plurality ofseeds for use with an implantation device of the type having a seedalignment channel, a hollow needle and a moveable plunger that causesseeds within the device to pass through the hollow needle and beimplanted within or adjacent to a target area, such as a tumor, locatedwithin a patient. The seed cartridge comprises an elongatedcylindrically-shaped core member having a seed conduit extendinglongitudinally therethrough, the seed conduit being adapted to retainthe plurality of seeds in end-to-end aligned relation prior to feedingthe seeds into the seed alignment channel of the implantation device.Locking means are provided to releasably connect the core member to theimplantation device so that the seed conduit is in aligned relation toand communication with the seed alignment channel of the implantationdevice. An elongated seed advancement push rod is slidably receivedwithin the seed conduit to move longitudinally within the seed conduitto cause the seeds contained within the seed conduit to advance into theseed alignment channel of the implantation device from the seedcartridge.

The BISC seed cartridge may be a preloaded, self-contained seedcartridge for brachytherapy or other operators and is adaptable for ahost of implant applicators. This delivery system comprises of aprotective outer casing that stores a pre-sterilized cartridgecontaining the seeds. The easy-lock and unloading of the seed cartridgefacilitates implantation by: (1) precluding exposure to staff before theimplant; (2) ensuring a verified seed count; (3) eliminating thepotential for seed spills or inadvertent loss due to seed manipulationin the brachyterapy hot room or operating suite; (4) efficient use ofphysician and operating room time by eliminating the need forautoclaving of the seeds/cartridge before use in the operating suite;(5) allowing rapid deposition of seeds that are preloaded with many moreseeds per cartridge than the standard number allowed by today'seedmagazines; and (6) limiting the potential for seed jamming or othermisapplication through the smooth mechanical action of the seedcartridge.

The foregoing specific objects and advantages of the invention areillustrative of those that can be achieved by the present invention andare not intended to be exhaustive or limiting of the possible advantageswhich can be realized. Thus, these and other objects and advantages ofthis invention will be apparent form the description herein or can belearned from practicing this invention, both as embodied herein or asmodified in view of any variations which may be apparent to thoseskilled in the art. Accordingly, the present invention resides in thenovel parts, constructions, arrangements, combinations and improvementsherein shown and described.

BRIEF DESCRIPTION OF THE DRAWINGS

The foregoing features and other aspects of the invention are explainedin the following description taken in connection with the accompanyingdrawings wherein:

FIG. 1 is a perspective view illustrating implantation of interstitialseeds using the fiberoptic-guided interstitial seed manual applicator inaccordance with the present invention;

FIG. 2 is a side elevation view of the fiberoptic-guided interstitialseed manual applicator in accordance with the present invention;

FIG. 3 is also a side elevation view further illustrating thefiberoptic-guided interstitial seed manual applicator shown in FIG. 2;

FIG. 4 is a longitudinal cross-sectional view of the roticulator ringand outer sheath of the fiberoptic-guided interstitial seed manualapplicator illustrated in FIG. 3;

FIG. 5 is an enlarged longitudinal cross-sectional view of the distalportion of the fiberoptic-guided interstitial seed manual applicatorillustrated in FIG. 3;

FIG. 6 is an exploded view of the seed transfer barrel mechanismillustrated in FIG. 5;

FIG. 7 is also an exploded view of the seed transfer barrel mechanismillustrated in FIG. 5;

FIG. 8 is a perspective view of the multichamber seed transfer barrelillustrated in FIG. 5;

FIG. 9 is a perspective view of the advancing pin and ring mechanismillustrated in FIG. 5;

FIG. 10 is an exploded view of the advancing pin and ring mechanism andseed transfer barrel mechanism illustrated in FIG. 5;

FIG. 11 is a longitudinal cross-sectional view of the seed biasingmechanism and fiberoptic plunger of the fiberoptic-guided interstitialseed manual applicator illustrated in FIG. 3;

FIGS. 12A-12C are longitudinal cross-sectional views illustrating theoperation of the multichamber seed transfer barrel and advancing pin andring mechanism in accordance with the present invention;

FIG. 13 is a side elevational view illustrating the seed lock mechanismof the fiberoptic-guided interstitial seed manual applicator illustratedin FIG. 5;

FIG. 14 is a perspective view of a second embodiment of thefiberoptic-guided interstitial seed manual applicator in accordance withthe present invention;

FIG. 15 is a side elevational view of the fiberoptic-guided interstitialseed manual applicator illustrated in FIG. 14;

FIG. 16 is a cross sectional view taken along line 1—1 shown in FIG. 15;

FIG. 17 is a cross sectional view taken along line 2—2 shown in FIG. 15;

FIG. 18 is a perspective view illustrating a seed cartridge inaccordance with the present invention;

FIG. 19 is a perspective view illustrating a core member of the seedcartridge shown in FIG. 18;

FIG. 20 is an elevational view of proximal end cap of the seed cartridgeshown in FIG. 18;

FIG. 21 is an elevational view of a distal end cap of the seed cartridgeshown in FIG. 18;

FIG. 22 is an exploded view of a second embodiment of the seed cartridgein accordance with the present invention;

FIG. 23 is a perspective view illustrating attachment of the seedcartridge shown in FIG. 22 to the fiberoptic-guided interstitial seedmanual applicator;

FIG. 24 is a perspective view of the alignment adaptor/seed repositoryused to attach the seed cartridge to the fiberoptic-guided interstitialseed manual applicator;

FIG. 25 is a cross-sectional view of the alignment adaptor/seedrepository illustrated in FIG. 24;

FIG. 26 is a partial perspective view of the seed cartridge illustratedin FIG. 22;

FIG. 27 is a cross-sectional view of the seed cartridge illustrated inFIG. 26;

FIG. 28 is a perspective view of a push rod for use with the seedcartridges illustrated in FIGS. 18 and 22;

FIGS. 29A-29H illustrate the sequence of events when loading a full seedcartridge into the fiberoptic-guided interstitial seed manual applicatorin accordance with the present invention;

FIG. 30 illustrates the seed cartridge operably connected to thefiberoptic-guided interstitial seed manual applicator in accordance withthe present invention;

FIG. 31A is a segmented sectional view illustrating the film bayonetused to pierce a film dam associated with the seed cartridge during theloading of seeds into the fiberoptic-guided interstitial seed manualapplicator shown in FIG. 30;

FIG. 31B is a segmented sectional view illustrating the advancement of ahollow push rod associated with the seed cartridge during the loading ofseeds into the fiberoptic-guided interstitial seed manual applicatorshown in FIG. 30;

FIGS. 32 and 32A are longitudinal cross-sectional views of a seedbiasing mechanism for use with the fiberoptic-guided interstitial seedmanual applicator in accordance with the present invention; and

FIGS. 33A-33E illustrate various brachytherapy procedures accomplishedusing the fiberoptic-guided interstitial seed manual applicator inaccordance with the present invention.

DETAILED DESCRIPTION

Referring to the drawings, there is illustrated a fiberoptic-guidedinterstitial seed manual applicator (“FOGISMA”) 1 in accordance with thepresent invention. FIG. 1 is illustrative of the general purpose of theFOGISMA device 1; e.g., to implant one or more seeds 3, 3 a, 3 b, . . .3 n in or around a tumor or other target tissue 2 within a patient. Itis understood that the present invention is not intended to be limitedsolely to brachytherapy procedures for implanting radioactive seeds, andmay be utilized for performing other medical implantation procedureswhere small bodies or objects are implanted within or near target tissueof a patient (e.g., chemotherapy). As such, the term “seed” as usedherein is intended to broadly mean an object or body to be implantedwithin a patient, including, but not limited to radioactive seeds usedin brachytherapy procedures.

The FOGISMA device 1 illustrated in FIG. 1 comprises an outer sheath 10and a hollow introducer needle 12 that is longitudinally displaceablerelative the outer sheath 10 for implanting seeds 3, 3 a, 3 b, . . . 3n. The distal end 13 of the outer sheath 10 is illustrated as being ingenerally apposed or abutting relationship to the tumor 2. Numerous“unfired” seeds 3 a, 3 b, . . . 3 n that have not yet been implanted ordeposited within or near the tumor 2 are also illustrated in FIG. 1 asbeing in aligned end-to-end relation to each other within the FOGISMAdevice 1.

With specific reference to FIGS. 2 and 3, the FOGISMA device 1 includesa distal end 13 (which is also the distal end of the outer sheath 10)and a proximal (control) end 15. As used herein, the term “distal” isintended to generally refer to the relevant portion of the FOGISMAdevice 1 that is closest to the distal end 13 (and furthest away fromthe proximal end 15) of the device 1 and the term “proximal” is intendedto generally refer to the relevant portion of the FOGISMA device 1 thatis furthest away from the distal end 13 (and closest t the proximal end15) of the device 1.

At the proximal end 15 of the FOGISMA device 1 is a housing 20 thatfacilitates handling and control of the device by the surgeon or otheroperator thereof. The housing 20 is preferably made of any suitablemolded material (e.g., plastic or stainless steel) that is acceptablefor such medical procedures and may be formed in two complimentaryhalves that may be fastened otherwise joined together to facilitateconstruction of the FOGISMA device 1.

While the housing 20 may be formed in a variety of differentconfigurations, it is preferred that the housing be of a generallyL-shaped pistol configuration for convenient and ready control andoperation of the FOGISMA device 1. The preferred housing 20 thereforeincludes a handle or grip portion 21 to be held by the surgeon oroperator of the device 1. At least a portion of the handle may be linedor coated with a thin layer of radiation insulating material (e.g.,lead) to prevent or minimize radiation exposure to the surgeon oroperator of the device 1.

As will be discussed further below, one embodiment of the housing 20comprises a seed advancement trigger 23 and an implantation lever 25 forcontrolling the operation of the FOGISMA device 1. The trigger 23 andlever 25 are each mounted proximate the handle portion 21 so that thesurgeon or operator of the FOGISMA device 1 may actuate the trigger 23and/or the lever 25 to control operation of the device 1 with the samehand that the surgeon or operator is using to hold the handle portion21.

A supplemental handle 27 may also be integrally formed or separatelymounted on the housing 20, which supplemental handle 27 may be used bythe surgeon or operator of the FOGISMA device 1 to transport and/orfurther steady the FOGISMA device 1 during operation. In FIGS. 2 and 3,the supplemental handle 27 is illustrated as preferably being mounted onthe top of the housing 20.

In one embodiment of the present invention, the outer sheath 10 of theFOGISMA device 1 is movable attached to the housing 20 using aroticulator ring 30 positioned between the outer sheath 10 and thehousing 20. With reference to FIGS. 3 and 4, the roticulator ring 30 isrotatably mounted on a forward end of the housing 20 in a conventionalmanner. The roticulator ring 30 includes a bore therethrough of adiameter slightly greater than the outer diameter of the outer sheath 10in order to permit the outer sheath to snugly pass therethrough duringassembly of the FOGISMA device 1. Internal threads 32 are formed withinthe bore of the roticulator ring 30 for interlocking engagement withexternal circumferential threads 11 formed in at least a portion of theexterior circumferential surface of the outer sheath 10. Thus, rotationof the roticulator ring 30 (in the direction of arrow B in FIG. 3)causes the outer sheath 10 to move longitudinally (in the direction ofarrow A) relative to the handle 20.

Accordingly, the surgeon or operator of the FOGISMA device 1 is able toprecisely control or modulate the depth of the introducer, needle 12within the target tissue 2 by rotating the roticulator ring 30 eitherclockwise for shallower insertions of needle 12 or counterclockwise fordeeper insertions of needle 12. Because the outer sheath 10 is intendedto abut against the tumor, tissue wall, template or grid duringoperation of the device 1, it is the length of introducer needle 12protruding beyond the outer sheath 10 when the insertion lever 25 isfully depressed that determines the relative needle length and therebydictates the depth of insertion. Calibrated markings or indicia 31 onthe roticulator ring 30 permit the surgeon or operator to precisely setthe depth of the introducer needle 12 according to the desiredspecification. That is, the indicia 31 indicate the relationship betweenthe distal end 13 of the outer sheath 10 and the distal tip 12 a of theintroducer needle 12.

Referring now to FIGS. 2, 3, 4 and 5, the outer sheath 10 extends fromthe handle 20 to the distal end 13 of the FOGISMA device 1. The outersheath 10 is preferably a rigid, elongated, hollow, tubular member.Alternatively, the outer sheath 10 be a flexible or deflectable tubularmember. The portion of the outer sheath 10 proximate the distal end 13of the device 1 is substantially enclosed to protect or cover thecomponents of the FOGISMA device 1 (including introducer needle 12)located within the outer sheath 10. An exit port 19 is formed in the endof the outer sheath 10 (proximate the distal end 13 of the device) inaligned relation to the introducer needle 12 to permit at least aportion of the needle 12 to pass therethrough during operation of theFOGISMA device 1 at the time of implantation of a seed 3.

A rigid, elongated, hollow, tubular inner sheath 34 may be locatedwithin the outer sheath 10 of the FOGISMA device 1. The length andoutside diameter of the inner sheath 34 is less than the length andinside diameter of the outer sheath 10 to facilitate assembly of theinner sheath 34 within the outer sheath 10. Like the outer sheath 10,the distal end of the inner sheath 34 (proximate the distal end 13 ofthe device 1) is substantially enclosed to protect or cover thecomponents of the FOGISMA device 1 located within the inner sheath 34.An exit port 38 is formed in the distal end of the inner sheath 34(proximate the distal end 13 of the device) in aligned relation with theexit port 19 of the outer sheath 10 and the introducer needle 12 topermit at least a portion of the needle 12 to pass therethrough duringset up and operation of the FOGISMA device 1. In the neutral ornon-implantation position, it is preferred that the distal end 12 a ofthe introducer needle 12 project just slightly through the exit port 38formed in the inner sheath 34. Preferably, the inner and outer sheaths34 and 10 are made from any suitable material that is capable ofwithstanding conventional medical instrument sterilization techniques(e.g., autoclave, radiation, x-ray, or ethylene oxide gas sterilization)and is acceptable for such medical procedures (e.g., plastic, stainlesssteel, etc.).

Referring to FIGS. 5, 6 and 7, the introducer needle 12 and a seedtransfer barrel housing 40 are located within the inner and outersheaths 10 and 34. The introducer needle 12 is hollow throughout itsentire length to allow seeds 3, 3 a, . . . , 3 n to pass therethrough.Accordingly, the diameter of the bore or hollow through the needle 12 isgenerally slightly larger than that of the seeds 3, 3 a, . . . 3 n. Theintroducer needle 12 preferably includes a flanged proximal end 12 b anda tapered or sharpened point at its distal end 12 a to facilitateinjection into body tissue.

The flanged proximal end 12 b of the needle 12 is preferably formedhaving internal threads for convenient attachment (e.g., threadedengagement) to mating threads formed on the circumference of thethreaded flange 42 of the seed transfer barrel housing 40, as will bediscussed further below. Alternatively, the needle 12 may be attached tothe seed transfer barrel housing 40 using a conventional Luer-Lokconnection.

As is best illustrated in FIGS. 5, 6 and 7, the seed transfer barrelhousing 40 is shown mounted within the inner and outer sheaths 10 and34. The seed transfer barrel housing 40 is generally cylindrical inshape having a smaller outside diameter than the inside diameter of theinner sheath 34. Projecting from one end 40 a of the barrel housing 40is the threaded flange 42 for securing the introducer needle 12 to thebarrel housing 40. As discussed above, the threaded flange 42 maycontain male threads or other means (e.g., Luer-Lok connection) forengagement with female threads formed on the proximal end 12 b, of theintroducer needle 12. It is understood, however, that the proximal end12 b of the introducer needle 12 could alternatively be formed with malethreads that screw into and engage threads formed within a femaleportion (e.g., aperture) of the barrel housing 40.

Preferably, a plurality of different interchangeable introducer needles12 should be available to the surgeon or operator of the FOGISMA device1. These needles 12 may, for instance, range from 1-20 cm in length andfrom 0.2-15 mm in diameter. Depending upon the particular application,therefore, the surgeon or operator of the device 1 may select theappropriate sized introducer needle 12 from the available selection ofinterchangeable needles and conveniently attach the selected needle 12to the threaded flange 42 of the seed transfer barrel housing 40.

The opposing or proximal end of the barrel housing 40 (opposite end 40a) is preferably open so that the barrel housing 40 has a longitudinallyextending bore running substantially therethrough to the end 40 a. Inaddition, a longitudinally extending aperture is formed through flange42 and end 40 a of the barrel housing 40, which aperture is in alignedrelation with the bore or hollow through the introducer needle 12 whenthe needle is secured to the flange 42. The diameter of the apertureextending through flange 42 and end 40 a is generally slightly largerthan that of the seeds 3, 3 a, . . . 3 n to facilitate transfer of theseeds through the aperture in the direction of arrow D in FIG. 5.

A cylindrically-shaped cover 43 having an opening formed therein issecured in a conventional manner to the open end of barrel housing 40.The opening in cover 43 is of such size as to permit introduction ofelongated, longitudinally extending member 60 through the opening andpartially into the bore of barrel housing 40. The elongated member 60 ispreferably a rigid, generally cylindrical member (e.g., injection moldedplastic) having one end located within the bore of barrel housing 40 andan opposing end proximate the proximal end 15 of the FOGISMA device 1.The elongated member may be lined or coated with a thin layer ofradiation insulating material (e.g., lead) to prevent of minimizeradiation exposure to the surgeon or operator during operation of thedevice 1.

Extending through the elongated member 60 are two parallellongitudinally extending channels, a fiberoptic channel 61 and a seedalignment channel 62. Fiberoptic channel 61 is aligned with the bore orhollow through the introducer needle 12 and the aperture through theflange 42. A plunger 65, which preferably contains a fiberoptic scope orother optical means, is positioned within the fiberoptic channel 61 andis movable within the channel 61 in response to movement of the lever25. A fiberoptic port 80 is provided in the proximal end 15 of theFOGISMA device 1 to facilitate connection of a fiberoptic scope or otheroptical means (not shown) to the plunger 65, as is illustrated in FIG.3.

In one preferred embodiment, a plunger 65 containing a fiberoptic scopeis utilized to provide visual assistance to the surgeon for implantguidance and to transfer the seed 3 from the multi-chamber transferbarrel 45 through the introducer needle 12 and into the tumor 2. It isunderstood, however, that other conventional optical means may besubstituted for the fiberoptic scope, such as a rod lens scope, Hopkinstype scope, laparoscope, endoscope, etc. The fiberoptic scope or otheroptical means may be inserted through a longitudinal bore through theplunger 65 for providing such visual assistance.

The seed alignment channel 62 formed within the elongated member 60 isgenerally slightly larger than the diameter of the seeds 3, 3 a, . . . 3n to facilitate transfer of the seeds in end-to-end aligned relationthrough the seed alignment channel 62 in the direction of arrow C inFIG. 5.

A seed transfer barrel 45 is positioned within the bore of the barrelhousing 40 and is rotatable relative the housing 40. Preferably, theseed transfer barrel 45 is generally cylindrical in shape with acentrally positioned, longitudinally extending opening therethrough. Amounting pin 47 supported on one end by the end 40 a of the barrelhousing 40 and on the opposing end by the elongated member 60 isreceived within the opening in the barrel 45 in order to rotatablysupport the barrel.

The seed transfer barrel 45 also comprises a plurality of parallel,equally spaced apart seed chambers 48, each of which extendslongitudinally through the barrel 45. In the embodiment illustrated inFIGS. 6, 7 and 8, four seed chambers 48 are shown, each of which isequally spaced apart at 90° from the preceding and subsequent chambers48. The length and diameter of each chamber 48 is such as to permit onlyone seed 3 to enter a given chamber 38 at one time. It is understood,however, that a greater or lesser number of seed chambers 48 may beutilized in accordance with the invention. For instance, the seedtransfer barrel 45 could be provided with only two seed chambers 48spaced apart from one another by 180°.

The barrel housing 40, cover 43, seed transfer barrel 45, advancing pinand ring mechanism 50, and elongated member 60 are preferably made in aconventional manner (e.g., injection molded) from any suitable materialthat is capable of withstanding conventional medical sterilizationtechniques (e.g., autoclave, radiation, x-ray, or ethylene oxide gassterilization), is acceptable for such medical procedures (e.g.,plastic, stainless steel, etc.) and may be manufactured to suitabletolerances. These components and/or the outer or inner sheaths 10, 34may also be lined or coated with a thin layer of radiation insulatingmaterial (e.g., lead) to prevent or minimize radiation exposure to thesurgeon or operator of the device 1.

As illustrated in FIGS. 3, 5, 11 and 12A-12C, a seed biasing member 70removable mounted on the housing 20 biases the seeds 3, 3 a, . . . 3 nwithin the seed alignment channel 62 toward the seed transfer barrel 45.The seed biasing member 70 preferably comprises an elongated hollow body71 that is closed on one end by a locking cap 72. A piston 73 isslidingly received within the hollow body 71. The piston 73 includes apiston rod 75 that projects longitudinally through an opening in thedistal end of the hollow body 71. A biasing member 74, such as acompression spring, is positioned within the hollow body 71 and biasesthe piston 73 away from the locking cap 72.

The elongated body 71 of the seed biasing member 70 is received within aseed insertion port 81 extending through the housing 20 in alignmentwith the seed alignment channel 62 of the elongated member 60. Thelocking cap 72 is removably secured to the proximal end 15 of housing 20in a conventional manner, such as via a tongue-in-groove arrangement.When installed on the FOGISMA device 1, the distal end of the piston rod75 engages the last seed 3 n within the seed alignment channel 62.Because the biasing member 74 biases the piston 73 and rod 75 toward thedistal end 13 of the FOGISMA device 1, the seeds 3, 3 a, . . . 3 n aresimilarly biased within the seed alignment channel 62 in the directionof arrow C in FIG. 5, thereby advancing the first seed 3 into the seedchamber 48 within the transfer barrel 45. Because each seed chamber 48can only accommodate one seed 3, the second seed 3 a within the seedalignment channel 62 may only advance after the seed transfer barrel 45rotates so that an empty seed chamber 48 becomes aligned with thealignment chamber 62.

On the circumference of the seed transfer barrel 45 are formed aplurality of equally spaced cut-out sections or cam portions 46, as isillustrated in FIGS. 5, 6, 7, 8, 10 and 12A-12C. As will be explainedfurther below, these cam portions 46 are used to selectively rotate ordrive the transfer barrel 45 relative the barrel housing 40 in order tofeed one seed 3 at a time into the introducer needle 12.

The transfer barrel 45 is driven in response to longitudinal movement ofa substantially rigid barrel advancing pin and ring assembly 50positioned within the bore of the barrel housing 40. With reference toFIGS. 5, 6, 7, 9, 10 and 12A-12C, the advancing pin and ring assembly 50preferably comprises a generally cylindrical-shaped ring portion 52 anda longitudinally extending advancing pin or member 51. An aperture isformed through the ring portion 52 for slidably receiving the distal endof the elongated member 60. The outside diameter of the ring portion 52is preferably slightly smaller than the inside diameter of the borewithin the barrel housing 40 to facilitate sliding movement of theadvancing pin and ring assembly 50 in the direction of arrow A relativethe barrel housing 40 and transfer barrel 45.

The barrel advancing pin and ring assembly 50 is biased toward thetransfer barrel 45 in the direction of arrow D in FIG. 5 by a springmember 58 (e.g., a compression spring). The spring member 58 ispreferably positioned within the bore of the barrel housing 40 betweenthe cover 43 and the ring portion 52. The outside diameter of the springmember 58 is smaller than the inside diameter of the bore in the barrelhousing 40 to facilitate insertion of the spring member 58 into thehousing 40. Similarly, the inside diameter of the spring member 58 islarger than the outside diameter of elongated member 60 to permit themember 60 to be inserted through the inside diameter of spring member58.

A linking shaft 55 is also located within the inner and outer sheaths 10and 34 and, in one embodiment, extends longitudinally therein betweenthe ring portion 52 of the barrel advancing pin and ring assembly 50 anda seed advancement trigger 23 located in a housing 20 at the proximalend 15 of the FOGISMA device 1, which will be described further below.The distal end of the linking shaft 55 is connected in a conventionalmanner to the ring portion 52 in order to control the longitudinalmovement of the barrel advancing pin and ring assembly 50 within thebarrel housing 40 relative the seed transfer barrel 45. As furtherillustrated in FIG. 7, two linking shafts 55 operatively connected tothe seed advancement trigger 23 may be utilized to control thelongitudinal movement of the advancing pin and ring assembly 50.Referring to FIG. 5, for each linking shaft 55, an aperture may beformed within cover 43 enclosing the barrel housing 40 to permit thelinking shaft 55 to freely move through the cover 43.

The advancing pin 51 of the barrel advancing pin and ring assembly 50projects longitudinally from the ring portion 52 in the direction ofarrow D in FIG. 5. A first barrel advancing tooth 51 a is formed on andprojects downwardly from the advancing pin 51 proximate the distal endof the pin. A second barrel advancing tooth 51 b is formed on andprojects downwardly from the advancing pin 51 proximate the ring portion52.

The first and second barrel advancing teeth 51 a and 51 b are configuredto interlock with and engage cam portions 46 a and 46 b, respectively,on the transfer barrel 45. In the preferred embodiment, the transferbarrel 45 is provided with a total of eight equally spaced cam portions46. Four identical proximal cam portions 46 b are circumferentiallylocated proximate the proximal end of the transfer barrel 45 and fouridentical distal cam portions 46 a are circumferentially locatedproximate the distal end of the transfer barrel 45. In this preferredarrangement, the distal cam portions 46 a are equally spaced along thecircumference of the transfer barrel 45 at 90° intervals and theproximal cam portions 46 b are similarly equally spaced along thecircumference of the transfer barrel 45 at 90° intervals, but areshifted 45° along the circumference of the transfer barrel 45 from thedistal cam portions 46 a.

A relieved portion 41 is formed in the end 40 a of the seed transferbarrel housing 40 proximate the first barrel advancing tooth 51 a of theadvancing pin 51. As illustrated in FIG. 12A, because the advancing pinand ring assembly 50 is biased by spring member 58 toward the end 40 aof the barrel housing 40, the first barrel advancing tooth 51 a isreceived within the relieved portion 41 and is disengaged from thedistal cam portion 46 a of the transfer barrel 45, while the secondbarrel advancing tooth 51 b is in interlocking engagement with theproximal cam portion 46 b of the transfer barrel 45. In this position, aseed 3 a located within alignment chamber 62 is biased by the seedbiasing member 70 into the empty seed chamber 48 of the transfer barrel45 that is aligned with the chamber 62. A seed 3 is also illustrated inFIG. 12A as being located within the adjacent seed chamber 48.

When the seed advancement trigger 23 is depressed by the surgeon oroperator of the FOGISMA device 1, the movement of the trigger 23overcomes the biasing force of the spring member 58 and causes thelinking shaft 55 to move longitudinally within the inner sheath 34toward the proximal end 15 of the device 1. As is illustrated in FIG.12B, such longitudinal movement of the linking shaft 55 causes thebarrel advancing pin and ring assembly 50 to move longitudinally withinthe barrel housing 40 in a direction toward proximal end 15. At the endof the trigger stroke, the first barrel advancing tooth 51 a moves outof the relieved portion 41 and engages a distal cam portion 46 a of thetransfer barrel 45, while the second barrel advancing tooth 51 bdisengages from the proximal cam portion 46 b of the transfer barrel 45.Engagement of the first barrel advancing tooth 51 a with one of thedistal cam portions 46 a causes the seed transfer barrel (and seed 3 a)to rotate a predetermined amount. In the preferred embodiment having atotal of eight equally spaced cam portions 46, this rotation of themultichamber transfer barrel 45 is precisely one eight of a revolution.Thus, seeds 3 and 3 a are illustrated in FIG. 12B as having rotated withtransfer barrel 45 precisely 45° in the counterclockwise direction.

Referring to FIG. 12C, upon release of the trigger 23 by the surgeon oroperator, the spring member 58 biases the advancing pin and ringmechanism 50 back to its original position with the first barreladvancing tooth 51 a again received within the relieved portion 41 anddisengaged from the distal cam portion 46 a of the transfer barrel 45,while the second barrel advancing tooth 51 b engages with one of theproximal cam portions 46 b of the transfer barrel 45. Engagement of thesecond barrel advancing tooth 51 b with one of the proximal cam portions46 b causes the seed transfer barrel 45 to further rotate apredetermined amount. In the preferred embodiment having a total ofeight equally spaced cam portions 46, this further rotation of themultichamber transfer barrel 45 is precisely one eighth of a revolution(or a total of one quarter a revolution from depression of the trigger23 to release thereof). In this position, the next or subsequent seed 3b (not shown) within alignment chamber 62 that was adjacent to ejectedseed 3 a is biased by the seed biasing member 70 into the empty seedchamber 48 of the transfer barrel 45 that is aligned with the chamber62. In addition, seeds 3 and 3 a have rotated with transfer barrel 45another 45° in the counterclockwise direction.

In the preferred embodiments described and illustrated herein, theFOGISMA device 1 is ready for firing when the seed chamber 48(containing a single seed 3) of the multichamber seed transfer barrel 45rotates 180° from the point where seed 3 was initially biased into thechamber 48 (i.e., when chamber 48 was aligned with seed alignmentchannel 62) to a position where chamber 48 containing that seed 3 isaligned with fiberoptic channel 61 and the bore through introducerneedle 12.

To prevent seed 3 in this firing position from prematurely dischargingfrom chamber 48 (e.g., should the needle 12 be pointed in a downwarddirection such that the force of gravity may cause seed 3 to prematurelydischarge from chamber 48 and continue through needle 12), a reducibleseed lock 85 is preferably provided in the longitudinal opening of thethreaded flange 42 of the barrel housing 40, as illustrated in FIGS. 5and 13. The reducible seed lock 85 preferably comprises a spring member86. Spring member 86 may be a flat, elongated metal or plastic springhaving a distal end 86 a and a proximal end 86 b. A portion 87 of thethreaded flange 42 is relieved within the longitudinal opening passingthrough the threaded flange 42 for receiving the distal and proximalends 86 a and 86 b of the spring member 86. The relieved portion 87 issufficiently large to permit the ends 86 a and 86 b to expandlongitudinally when spring member 86 is compressed.

When the distal and proximal ends 86 a and 86 b of the spring member 86are inserted within relieved portion 87, a portion 86 c of spring member86 projects into the longitudinal opening in threaded flange 42. Becausespring portion 86 c projects into the opening, spring portion 86 cpresents a seed 3 prematurely discharging from chamber 48 from passingthrough the flange 42 into needle 12. Only when a longitudinal force isprovided to seed 3 sufficient to overcome (compress) spring 86 withinrelieved portion 87 (e.g., when fiberoptic plunger 65 is advanced downthe fiberoptic channel 61, through the aligned seed channel 48 of thetransfer barrel 40 and into the aligned opening of flange 42) will seed3 be able to advance beyond the seed lock 85 and into the needle 12.

A second embodiment of the FOGISMA device 1 is illustrated in FIGS.14-17. Referring to FIG. 15, a cross-section of a housing 20 and theproximal portion of the outer sheath 10 of the FOGISMA device 1 areillustrated. Like the first embodiment described above, the housing 20of the second embodiment is preferably L-shaped and may be injectionmolded from a suitable plastic that is capable of maintaining accuratedimensional stability during and after repeated use and sterilizations.The housing 20 may be formed in two complimentary halves that may befastened or otherwise joined together to facilitate construction of theFOGISMA device 1.

The outer sheath 10 of this second embodiment is similar to thatdescribed above with respect to the first embodiment. Although onlypartially illustrated in FIG. 15, a distal portion 10 a of outer sheath10 includes a first bore extending longitudinally through the distal end13 of the device 1 in a similar manner to the outer sheath of the firstembodiment. A proximal portion 10 b of the outer sheath 10 having asecond bore is connected to the distal portion 10 a. The second bore ofouter sheath portion 10 b is preferably larger than the first bore ofouter sheath portion 10 a so that the proximal portion 10 b mayslidingly receive at least the distal end of the housing 20.

A control level 125 is pivotally mounted proximate the handle portion 21so that the surgeon or operator of the FOGISMA device 1 may actuate thelevel 125 to control operation of the device 1 with the same hand thatthe surgeon or operator is using to hold the handle portion 21. Controllever 125 is pivotally mounted to housing 20 by pin 150. The controllever 125 comprises an arcuate, first pinion section 101 within housing20 having a plurality of gear teeth formed thereon. A spring 151 havingone end affixed to handle portion 21 and the opposing end affixed to thecontrol lever 125 biases the control lever about pin 150 to a neutralposition A, as illustrated in FIG. 15.

Referring to FIGS. 15, 16 and 17, a first rack 102, which is supportedand longitudinally displaceable within the housing 20, includes aplurality of gear teeth for interlocking engagement with the pinionsection 101 of the control lever 125. A first gear 103 is rotatablymounted within housing 20 and has gear teeth that interlocking engagethe gear teeth of first rack 102. A second gear 104 is attached to firstgear 103 so that the first and second gears rotate together and do notrotate relative to one another. The first and second gears 103, 104 may,for instance, be mounted on the same supporting shaft or be formedintegrally together as a single unit. As is best illustrated in FIG. 16,second gear 104 is generally H-shaped, having a first set of gear teethcircumferentially formed on its major outside diameter and having asecond set of centrally located gear teeth circumferentially formed onits minor outside diameter.

A proximal portion of the plunger 65 is illustrated in FIG. 15. It isunderstood that the distal end of the plunger 65 continueslongitudinally through the fiberoptic channel 61 within portion 10 a ofthe outer sheath 10 toward the distal end 13 of the device 1. Theplunger 65 is substantially hollow 106 from end-to-end to facilitateinsertion of a fiberoptic scope (rigid or flexible) or other opticalmeans (e.g., rod lens scope, Hopkins type scope, laparoscope, endoscope,etc.) therein. The plunger 65 passes through an opening or fiberopticport 80 in the proximal end 15 of the housing 20, as illustrated in FIG.3, and terminates at its proximal end within a scope rest 160. The scoperest 160 is used to support the fiberoptic or optical scope, includingthe eyepiece, light guide post, camera head and light guide cable (notshown). A geared portion 105 of the plunger 65 proximate the second gear104 has formed thereon a plurality of gear teeth for interlockingengagement with the second set of gear teeth centrally located on thesecond gear 104.

A third gear 107 of generally H-shaped configuration comprises an outerset of gear teeth 107 a circumferentially formed on the major outsidediameter of the third gear 107 and an inner set of centrally locatedgear teeth 107 b circumferentially formed on the minor outside diameterof the third gear. The outer teeth 107 a engage the first set of teethon second gear 104 and the inner teeth 107 b engage the teeth formed onsecond rack 108, which second rack extends and is displaceablelongitudinally within housing 20.

The second rack 108 is preferably rectangular in shape and has aproximal and a distal end. The second rack 108 includes a bore extendinglongitudinally from the proximal end of the rack 108 at leastsubstantially to the distal end thereof. The distal end of an outersheath adjustment rod 155 is received within the bore and rotatablyconnected to the second rack 108. The proximal end of the rod 155extends through an opening in the proximal end 15 of the housing 20 andterminates in an adjustment knob 156. A plurality of pawls or gear teeth109 are supported by the rod 155 proximate its distal end and projectoutwardly through an opening formed in the second rack 108. In thismanner, rotation of the know 156 turns rod 155 relative to the secondrack 108, thereby causing the rod and associated pawls 109 to movelongitudinally within the opening formed in the second rack 108 (i.e.,the pawls move relative the second rack).

A fourth gear 110 is rotatably mounted within housing 20 and isrotatable in only one direction. The fourth gear 110 is a generallyH-shaped configuration comprising an outer set of gear teeth 110 acircumferentially formed on the major outside diameter of the fourthgear 110 and an inner set of centrally located gear teeth 110 bcircumferentially formed on the minor outside diameter of the fourthgear. The inner set of centrally located gear teeth 110 b interlockinglyengage pawls 109 of the second rack 108 for driving the fourth gear 110in a first direction. However, pawls 109 disengage from the teeth 110 bof the fourth gear 110 when the fourth gear is driven in the oppositedirection. As such, the second rack 108, pawls 109 and the fourth gear110 generally act as a continuous ratchet type assembly whereinlongitudinal movement of the second rack 108 in one direction causes thefourth gear 110 to rotate in that direction , while longitudinalmovement of the second rack 108 in the opposite direction disengagespawls 109 from the fourth gear 110 without the moving the fourth gear. Aone way clutch could also be operatively connected to the fourth gear110 to permit the gear to be driven in only one direction (i.e.,clockwise direction) by pawl 109 of the second rack 108.

The proximal portion 10 b of the outer sheath 10 includes a set of gearteeth 112 that projects inwardly within the second bore of portion 10 b.the outer set of teeth 110 a formed on the fourth gear 110 partiallyproject through an opening or slot formed in the housing 20 in order tointerlockingly engage the inwardly projecting gear teeth 112 formed onthe proximal portion 10 b of the outer sheath 10 so that rotation of thefourth gear 110 causes the outer sheath 10 to move longitudinallyrelative the housing 20.

As mentioned above, the distal portion 10 a of outer sheath 10 has afirst bore extending longitudinally to the distal end 13 of the device 1in a similar manner to the outer sheath of the first embodiment. Whilenot specifically illustrated in FIGS. 15-17, it is understood that thesecond embodiment of the FOGISMA device 1 comprises at least theintroducer needle 12, seed transfer barrel housing 40, seed transferbarrel 45, advancing pin and ring assembly 50, linking shaft 55,elongated member 60, plunger 65 and seed lock 85 described above andillustrated in FIGS. 1-13 with respect to the first embodiment. Thesecomponents are located within the first bore of the distal portion 10 aof the outer sheath 10 proximate the distal end 13 of the FOGISMA device1.

Referring now to FIG. 15, the linking shaft 55 has a distal end that isoperatively connected to the advancing pin and ring mechanism 50 forcontrolling the longitudinal movement of the mechanism 50 relative tothe multichamber seed transfer barrel 45. The proximal end of thelinking shaft 55 is illustrated in FIG. 15 as being operativelyconnected to a hook member 117. Hook member 117 is preferably anelongated bar or rod having an upwardly extending flexible hook 117 aprojecting therefrom. The hook member 117 is located within and slidablysupported by the housing 20 between the third and fourth gears 107, 110.

A fifth gear 114 is located within and rotatably supported by housing 20proximate the second rack 108. The fifth gear 114 includes a set of gearteeth circumferentially formed thereon for interlockingly engaging acorresponding set of gear teeth 108 a formed on at least a portion of asecond rack 108. The gear teeth on the fifth gear 114 alsointerlockingly engage corresponding gear teeth formed on a third rack115. Like the hood member 117, the third rack 115 is also located withinand slidably supported by the housing 20 between the third and fourthgears 107, 110. A flexible hook or tooth 116 projects downwardly fromthe third rack 115 so that when the third rack 115 is drivenlongitudinally toward the hook member 117, the downwardly extending hook117 a in the hook member 117.

It is understood that control lever 125 and gears 103, 104, 107, 110 maybe rotatably mounted within the housing 20 in a conventional manner,such as by mounting each gear on a shaft or pin and rotatably supportingthe shaft by a pair of suitable bearings or bushings mounted within thehousing 20. In addition, hook member 117 and racks 102, 108, 115 may beslidably supported within the housing using suitable journals orbearings mounted within the housing 20.

The operation of the second embodiment of the FOGISMA device 1 isdiscussed below. Initially, to prepare the device 1 for operation, thesurgeon or operator of the device will set the desired spacing betweenimplanted seeds 3, 3 a, . . . , 3 n by turning the adjustment knob 156.As knob 156 is manually rotated, outer sheath adjustment rod 155 ismoved longitudinally relative the second rack 108, thereby moving pawls109 longitudinally within the opening of the second rack 108 relativethe fourth gear 110. Because pawls 109 engage and drive the fourth gear110, which fourth gear in turn drives the outer sheath 10 longitudinallyrelative the housing 20, the surgeon or operator of the FOGISMA device 1is able to precisely set and control the longitudinal distance that theouter sheath 10 travels or advances relative the housing 20 each timethe control lever 125 is fully actuated. That is, the surgeon oroperator is able to precisely adjust the timing when pawls 109 engagethe gear teeth of the fourth gear 110.

As illustrated in FIGS. 14 and 15, control lever 125 is capable of beingactuated by the surgeon or operator of the FOGISMA device 1 from neutralposition A to position B (actuated approximately 60° from position A) toposition C (actuated approximately 75° from position A) and back toposition A. As will be discussed in greater detail below, when the lever125 is actuated from point A to point B as is illustrated in FIG. 15,the fiberoptic plunger 65 (and fiberoptic scope or other optical meansreceived within the bore 106) is advanced through the seed transferbarrel 45 to the distal end 12 a of the introducer needle 112. When thelever 125 is further actuated from point B to point C as is illustratedin FIG. 15, the outer sheath 10 is advanced a predetermined distance (asset by the surgeon or operator using the adjustment knob 156). Finally,when the lever 125 is released by the surgeon or operator of the FOGISMAdevice 1 and automatically returns from point C to point A by virtue ofcontrol lever spring 151 as illustrated in FIG. 15, the fiberopticplunger 65 (and fiberoptic scope or other optical means) are withdrawnfrom the needle 12 and seed transfer barrel 45 toward the proximal end15 of the device 1 and the seed transfer barrel 45 is indexed apredetermined amount.

Referring to FIG. 15, when the control lever 125 of the FOGISMA device 1is actuated from point A to point B, the control lever 125 pivots aboutpin 150, thereby causing the pinion section 101 of the control lever 125to rotate in a counterclockwise direction. Because the gear teeth onpinion section 101 engage mating gear teeth on the first rack 102, thefirst rack 102 is caused to move or is driven longitudinally toward thedistal end 13 of the device 1. Such longitudinal displacement of thesecond rack 102 causes the first gear 103 to rotate in acounterclockwise direction due to the interlocking engagement of thegear teeth on the second rack 102 and first gear 103. Because secondgear 104 is fixed to the first gear 103, the second gear 104 is alsocaused to rotate in the counterclockwise direction. Suchcounterclockwise rotation of the second gear 104 causes the fiberopticplunger 65 (and fiberoptic scope or other optical means retainedtherein) to move longitudinally toward the distal end 13 of the device 1due to the interlocking engagement of the first set of centrally locatedgear teeth on the second gear 104 with the gear teeth 105 formed on theplunger 65. Such longitudinal movement of the plunger 65 also compressesplunger return spring 123 with sufficient force to overcome the opposingbiasing force of spring 123.

Once the lever 125 is actuated to point B (approximately 60° from pointA), the last or proximal-most gear tooth 105 formed on the plunger 65engages the teeth on the second gear 104. Since there are no teeth 105formed on the plunger after this point or last tooth 105, continuedcounterclockwise rotation of gear 104 no longer longitudinally advancesthe plunger 65 toward the distal end 13 of the device 1.

Accordingly, when the lever 125 is at point B, the plunger 65 hasadvanced through the fiberoptic channel 61 in the elongated member 60,through chamber 48 of the seed transfer barrel 45, through threadedflange 42 to approximately the distal end 12 a of the introducer needle12. Thus, a seed 3 that had previously been loaded into chamber 48 ofthe transfer barrel 45 will have been fired or forced by the advancingplunger 65 out of the chamber 48, through the introducer needle 12, anddeposited within the tumor 2.

The fiberoptic scope or other optical means (e.g., rod lens scope,Hopkins type scope, laparoscope, endoscope, etc.) (not shown) that ispreferably retained within the bore 106 through the fiberoptic plunger65, permits the surgeon or operator of the device 1 to view the proximalend of the seed 3 to ensure that the “fired” seed 3 exits the introducerneedle 12 into the tumor 2 or other tissue. The fiberoptic scope orother optical means also facilitates visual inspection of the implantedseed 3 within the tumor 2 or other tissue. Such visual inspection of theimplanted seed 3 permits the surgeon or operator of the device 1 toverify that the seed 3 had been implanted in the proper location of thetumor 2, or tissue. Such visual verification may be quite valuablewhere, for instance, there exists the possibility that the introducerneedle 12 has penetrated beyond the tumor or tissue wall wherebyimplanted seeds 3 might otherwise be deposited in undesirable locationsor orifices within the patient.

In addition to advancing the plunger 65 to the distal end 12 a of theintroducer needle 12 when the control lever 125 is actuated from point Ato point B, such counterclockwise rotation of the second gear 104 causesthe third gear 107 to rotate in a clockwise direction due to theinterlocking engagement of the mating outer circumferential gear teethon the second and third gears. Such clockwise rotation of third gear 107thereby causes the second rack 108 and pawl 109 to move longitudinallytoward the proximal end 15 of the FOGISMA device 1.

Such longitudinal movement of the second rack 108 in the proximaldirections causes: (1) the fifth gear 114 to rotate in acounterclockwise direction due to the interlocking engagement of gearteeth on the second rack 108 and fifth gear 114; and (2) pawls 109 tomove longitudinally with the second rack in the proximal direction intocontact with the inner gear teeth centrally located on the fourth gear110 (but does not yet cause the fourth gear 110 to rotate). When thefifth gear 114 is driven in the counterclockwise direction by the secondrack 108, the fifth gear 114 causes the third rack 115 to movelongitudinally toward the distal end 13 of the device 1 due to theinterlocking engagement of gear teeth on the fifth gear 114 and thethird rack 115. Such longitudinal movement of the third rack 115 causethe engaging hook 116 on the third rack 115 to move toward (but not yetengage) the hook 117 a of hook member 117.

Thus, when the control lever 125 is actuated to point B as illustratedin FIG. 15, the fiberoptic plunger 65 (and fiberoptic scope or otheroptical means) is advanced to the distal end 12 a of the introducerneedle 12 and the outer sheath 10 is about to advance.

Referring to FIG. 15, when the control lever 125 of the FOGISMA device 1is further actuated from point B to point C (e.g., approximately 75°from point A), the control lever 125 pivots further about pin 150,thereby causing the pinion section 101 of the control lever 125 tocontinue to rotate in a counterclockwise direction. Such continuedcounterclockwise rotation of pinion section 101 drives the first rack102 longitudinally toward the distal end 13, thereby causing the firstand second gears 103 and 104 to rotate further in the counterclockwisedirection. Because the gear teeth formed on the second gear 104 nolonger engage any additional gear teeth 105 formed on the fiberopticplunger 65, the plunger 65 (and fiberoptic scope or optical means) doesnot advance further longitudinally in the direction of the distal end 13of the FOGISMA device 1. However, the distal end of the plunger 65remains in its advanced position at the distal end 12 a of theintroducer needle 12 (with spring 123 remaining in a compressed state).

The continued counterclockwise rotation of the second gear 104 drivesthe second rack 108 further in the longitudinal direction toward theproximal end 15 of the device 1. Such further movement of the secondrack 108 drives the fifth gear 114 in the clockwise direction, therebydriving the third rack 115 longitudinally toward the hook member 117 sothat the engaging hook 116 on the third rack 115 releasingly engages thehook 117 a of the hook member 117. Because the hooks 116, 117 a are madeof a flexible, resilient material, the hooks deform slightly to permitthe engaging hook 116 to travel slightly beyond the engage hook 117 a.Upon engagement with one another, the hooks 116, 117 a resilientlyreturn to their original shape to maintain such locking engagement untila sufficient releasing force is applied to again deform the hooks whenthe third rack 115 is moved longitudinally away from hook member 117 inthe proximal direction.

In addition, the continued longitudinal movement of the second rack 108(and therefore of the pawls 109) in the direction of the proximal end 15of the device 1 causes pawls 109 to engage the centrally located innergear teeth 110 b formed in the fourth gear 110, thereby causing thefourth gear 110 to rotate in the clockwise direction (fourth gear 110 isonly permitted to rotate in the clockwise direction). When the fourthgear 110 rotates in the clockwise direction, the outer sheath 10 iscaused to precisely move or advance longitudinally relative housing 20toward the distal end 13 of the device 1 due to the interlockingengagement of the outer circumferential gear teeth 110 a formed in thefourth gear 110 with the gear teeth 112 formed on the interior of theouter sheath 10.

Since the distal end 13 of the outer sheath 10 is intended to abut thewall of the tumor 2 or other body tissue of the patient, a template or agrid during operation of the FOGISMA device 1, the above-describedlongitudinal movement of the outer sheath 10 in the distal directionrelative housing 20 (and therefore relative introducer needle 12) willcause the introducer needle 12 to withdraw a predetermined distance fromthe tumor 2 or other tissue in which the needle has penetrated, therebyleaving a seed 3 (previously advanced by plunger 65 through theimplantation needle 12) implanted in the tumor 2. The predetermineddistance that the needle 12 moves relative the outer sheath 10 due toadvancement of the outer sheath relative the housing 20 controls thespacing between implanted seeds 3, 3 a, . . . , 3 n within the tumor 2and is established by the surgeon or operator of the FOGISMA device 1 byturning the adjustment knob 156 as described above to adjust the timingwhen pawls 109 engage the fourth gear 110.

Thus, when the control lever 125 is actuated to point C as illustratedin FIG. 15, the fiberoptic plunger 65 (and fiberoptic scope or otheroptical means) remains in the advanced position at the distal end 12 aof the introducer needle 12 and the outer sheath 10 has been advanced apredetermined distance toward the distal end 13 of the device 1 relativethe housing 20, thereby partially withdrawing the needle 12 from thetumor 2 by that predetermined distance.

With reference to FIG. 15, when the actuated control lever 125 of theFOGISMA device 1 is thereafter released by the surgeon or operator, thespring 151 biases the control lever 125 back to the neutral positionfrom point C to point A. When this occurs, the control lever 125 pivotsabout pin 150, thereby causing the pinion section 101 of the controllever 125 to rotate in a clockwise direction. Such clockwise rotation ofpinion section 101 drives the first rack 102 longitudinally toward theproximal end 15, thereby causing the first and second gears 103 and 104to rotate in a clockwise direction. The clockwise rotation of secondgear 104 causes the gear teeth formed on the second gear 104 to onceagain engage the gear teeth 105 formed on the fiberoptic plunger 65,thereby driving (with the assistance of spring 123) the plunger 65 (andfiberoptic scope or other optical means) longitudinally in the directionof the proximal end 15 of the FOGISMA device 1. At this point, thedistal end of the plunger 65 is returned to its original position and nolonger extends within the introducer needle 12 or seed transfer barrel45.

The clockwise rotation of the second gear 104 also drives the secondrack 108 in the longitudinal direction back to its original positiontoward the distal end 13 of the device 1. Such return movement of thesecond rack 108 also causes pawls 109 to disengage and move away fromthe fourth gear 110. The fourth gear 110, which can only rotate in theclockwise direction, is not driven by the disengaging pawls 109 when thesecond rack moves longitudinally toward the distal end 13 of the device1. As such, the outer sheath 10 does not move when the control lever 125returns from point C to the neutral position at point A and the controllever 125 remains in the advanced position which occurred when the lever125 was previously actuated from point B to point C.

The return movement of the second rack 108 also drives the fifth gear114 in the counterclockwise direction, thereby driving the third rack115 longitudinally away the hook member 117 to its original position.Because of the engagement of hooks 116, 117 a, the movement of the thirdrack 115 toward the proximal end 15 of the device 1 causes the hookmember 117 to also move longitudinally in the proximal direction. Suchlongitudinal movement of the hook member 117 causes the advancing pinand ring assembly 50 to similarly move longitudinally relative the seedtransfer barrel 45 toward the proximal end 15 of the FOGISMA device 1due to the connection of the hook member 117 with the advancing pin andring assembly 50 by the linking shaft 55, thereby compressing springmember 58 located within the seed transfer barrel housing 40.

As discussed above with respect to FIGS. 5-10 and 12A-12C, when theadvancing pin and ring assembly 50 moves in the proximal directionrelative the seed transfer barrel 45, the first barrel advancing tooth51 a formed on the assembly 50 moves out of the relieved portion 41 andengages a distal cam portion 46 a of the transfer barrel 45, while thesecond barrel advancing tooth 51 b disengages from the proximal camportion 46 b of the transfer barrel 45. Engagement of the first barreladvancing tooth 51 a with one of the distal cam portions 46 a causes theseed transfer barrel (and seed 3 a contained therein) to rotate apredetermined amount, as is illustrated in FIG. 12B. As mentioned above,a preferred embodiment of the seed transfer barrel 45 includes a totalof eight equally spaced cam portions 46, so that the predeterminedrotation of the multichamber transfer barrel 45 is precisely one eighthof a revolution.

Once the transfer barrel 45 is actuated that predetermined amount (e.g.,one eighth revolution) by the first barrel advancing tooth 51 a, theresultant force opposing continued longitudinal movement of hook member117 in the proximal direction exceeds the holding force of the engagedhooks 116, 117 a, thereby deforming and disengaging the hooks from oneanother. The third rack 115 continues to be driven in the proximaldirection back to its original position and the spring member 58 biasesthe advancing pin and ring mechanism 50 distally back to its originalposition with the first barrel advancing tooth 51 a again receivedwithin the relieved portion 41 and disengaged from the distal camportion 46 a of the transfer barrel 45, while the second barreladvancing tooth 51 b again engaging one of the proximal cam portions 46b of the transfer barrel 45. Engagement of the second barrel advancingtooth 51 b with one of the proximal cam portions 46 b causes the seedtransfer barrel to further rotate a predetermined amount. In theembodiment of the seed transfer barrel 45 having a total of eightequally spaced cam portions 46, this predetermined rotation of themultichamber seed transfer barrel 45 is precisely one eighth of arevolution (or a total of one quarter of a revolution from actuation ofthe control lever 125 to release thereof), as illustrated in FIG. 12C.

By rotating the seed transfer barrel 45 a total of 90° when the controllever 125 returns to neutral point A from point C, the next orsubsequent seed 3 b (not shown) within alignment chamber 62, which seed3 b was adjacent to the seed 3 a previously loaded into the adjacentseed chamber 48, is biased into the empty seed chamber 48 of thetransfer barrel 45 that is now aligned with the seed alignment channel62. In addition, the seed chamber 48 containing seed 3 as illustrated inFIG. 12C has rotated 90° so that the seed chamber 48 containing seed 3is now aligned with fiberoptic channel 61, plunger 65, the bore throughintroducer needle 12 and the aperture through flange 42. Thus, the seed3 illustrated in FIG. 12C is now in position to be fired or driven bythe plunger 65 into the tumor 2 when the surgeon or operator of theFOGISMA device 1 once again actuates the control lever 125 from point Ato point B.

It is understood that the number of seed channels 48 and cam portions 46in the seed transfer barrel 45 may vary depending upon the applicationand that the above-described embodiment of the seed transfer barrel 45having eight cam portions and four seed transfer channels isillustrative of one preferred arrangement. Another possible arrangementcould include two seed chambers 48 spaced 180° apart from one anotherand four cam portions 46 (each providing 45° rotation of the seedtransfer barrel 45 when engaged by one of the advancing pin teeth 51 a,51 b of the advancing pin and ring assembly 50).

Thus, when the control lever 125 returns from point C to the neutralposition at point A as illustrated in FIG. 15, the fiberoptic plunger 65(and fiberoptic scope or other optical means) retract from theintroducer needle 12 and seed transfer barrel 45 to the originalposition within the fiberoptic channel 61, and the seed transfer barrel45 is rotated a predetermined amount in order to place the next seedwithin the transfer barrel in position for firing through needle 12 andto load another seed from the seed alignment channel 62 into an emptyseed chamber 48 in the barrel 45.

It is also understood that the present invention is not limited to anyparticular tooth configuration of the various gears, pinions and racksdescribed herein. However, it is preferable that the teeth of thesegears, pinions and racks be very fine and precise to facilitate accuratecontrol and operation of the FOGISMA device 1. These gears, pinions andracks may preferably be manufactured in a conventional manner from anysuitable material that is capable of withstanding conventional medicalinstrumentation sterilization techniques (e.g., autoclave, radiation,x-ray, or ethylene oxide gas sterilization) and is acceptable for suchmedical procedures (e.g., plastic, stainless steel, etc.).

A first disengagement lever 124 having a wedge-shaped portion may alsobe provided on the housing 20 to selectively disengage the third gear107 from the second rack 108, as is illustrated in FIGS. 14 and 15.Selective actuation of the first disengagement lever 124 will cause thegear 107 to move slightly away from the second rack 108, or vice versa,just enough to disengage their respective gear teeth. When the thirdgear 107 is disengaged from second rack 108, the surgeon or operator ofthe device 1 can actuate the control lever 125 to move the fiberopticplunger 65 longitudinally through the device 1 without operating any ofthe other components of the device 1. This may be useful during set-upof the FOGISMA device 1, for instance, to initially insert the needle 12into the target tissue prior to implantation. Thus, the advanced plunger65 may be used as a stylet to prevent introduction of tissue into thebore of the needle 12 and for viewing the implantation site prior toimplantation. Once this is accomplished, the first disengagement lever124 may be actuated to return to its original position wherein the thirdgear 107 and second rack 108 are again in meshing engagement with oneanother.

A second disengagement lever 122 having a wedge-shaped portion may alsobe provided on the housing 20 to selectively disengage the fourth gear110 from the gear teeth 112 formed on the interior of the outer sheath10, as is illustrated in FIGS. 14 and 15. Selective actuation of thesecond disengagement lever 122 will cause the fourth gear 110 to moveslightly away from gear teeth 112 on the outer sheath 10 just enough todisengage the two from one another. When the fourth gear 110 is indisengaged position relative outer sheath gear teeth 112, the surgeon oroperator of the device 1 can manually adjust the longitudinal locationof the outer sheath 10 relative the housing 20. This may be usefulduring set-up of the FOGISMA device 1, for instance, to set the desiredstarting position of the outer sheath 10. Calibrated markings or indica(not shown) may be provided on the housing 20 relative the proximal endof the outer sheath 10 to precisely set the depth of the introducerneedle 12 according to the desired specification. Selective actuation ofthe second disengagement lever 122 may also be useful during set-up ofthe FOGISMA device 1, for instance, to load seeds 3, 3 a, . . . , 3 ninto respective chambers 48 of the multichamber seed transfer barrel 45in order to position a seed in the firing position (e.g., in alignedrelation to the plunger 65 and needle 12). Once set-up is complete, thesecond disengagement lever 122 may be actuated to return to its originalposition wherein the fourth gear 110 again interlockingly engages theouter sheath gear teeth 112.

The housing 20 of the FOGISMA device 1 may also be provided with a seedcounter indicator 9 for visually providing a numerical cumulative seedtally of implanted “fired” seeds 3 and “unfired” seeds 3 a, 3 b . . . ,3 n remaining in the device 1. The seed counter 9 may preferably be aconventional gear-type counter mechanism that actuates each time a seed3 is fired or discharged from the device 1 through needle 12. Theconventional gear-type counter mechanism may, for instance, beoperatively connected to any one of the elements (e.g., control leverpinion section 101, first rack 102, first gear 103, second gear 104, orplunger gear teeth 105) that drive the plunger 65 through the needle 12to fire or discharge a seed 3 from the device 1. In the embodimentillustrated in FIG. 15, the seed counter indicator 9 is actuated by anactuator rod 126 that is connected to the proximal end of the secondrack 108. Thus, each time the second rack 108 is driven longitudinallyto advance the multichamber seed transfer barrel 45, the actuator rod126 moves the engagement with the seed counter indicator 9 and causesthe seed counter 9 to actuate one numerical value. The seed counterindicator 9 includes a visual display of the number of seeds fired fromthe device 1, which visual display is preferably provided on the housing20, as illustrated in FIGS. 2, 3, 14 and 15.

In either of the above-described embodiments of the FOGISMA device 1, itis necessary to load the seeds 3, 3 a, . . . , 3 n into the device 1.Referring to FIGS. 18-21, there is illustrated a BrachytherapyInterstitial Seed Cartridge (“BISC” or “seed cartridge”) 200 that isideally suited for use in conjunction with the FOGISMA device 1. It isunderstood, however, that the seed cartridge 200 may also be easilyadapted to fit existing interstitial seed applicators.

In one embodiment of the seed cartridge 200 illustrated in FIGS. 18-21,a cylindrically-shaped inner core 210 is provided having multiplechambers 212 extending longitudinally therethrough. The inner core 210is preferably made of either plastic or metal, and includes a pluralityof substantially parallel seed chambers or conduits 212 a, 212 b, 212 cand 212 d extending longitudinally from a proximal end 214 of the core210 to a distal end 215 of the core 210.

Each conduit 212 a, 212 b, 212 c, 212 d is generally slightly largerthan the diameter of the seeds, 3, 3 a, . . . 3 n for receiving theseeds in end-to-end aligned relation. While the length of the inner core210 dictates the number of seeds that may be held in each seed conduit212, each conduit 212 a, 212 b, 212 c, 212 d preferably holds up to 25seeds 3, 3 a, . . . 3 n in end-to-end aligned relation.

For each seed conduit 212 a, 212 b, 212 c, 212 d, a longitudinal slot oropening 220 is formed in the circumference of the inner core 210, whichopening 220 extends from the proximal end 214 to the distal end 215 ofthe inner core 210. Each opening 220 is tangential to one of the seedconduits 212 a, 212 b, 212 c, 212 d so that each seed conduit is open orslotted about the circumference of the inner core 210.

The inner core 210 is contained within a cylindrically-shaped outersleeve 230. The outer sleeve 230 includes a bore extendinglongitudinally from the proximal end 232 of the outer sleeve 230 to thedistal end 233 of the outer sleeve. The diameter of the bore through theouter sleeve 230 is preferably slightly larger than the outside diameterof the inner core 210 so that the inner core 210 may be received withinthe bore of the outer sleeve 230.

The outer sleeve 230 is preferably made from lead or steel in order toeffectively shield personnel handling the seed cartridge 200 fromexposure to the seeds 3 contained therein (e.g., radioactive or chemicalexposure). It is understood, however, that other materials such asplastic may be utilized in making the outer sleeve 230 and that aprotective insulating layer of lead or steel may be applied or bonded tothe outer sleeve 230 to provide the desired protection from radiationexposure.

The outer sleeve 230 has a circumferential slot 235 extending from theproximal end 232 to the distal end 233 of the sleeve. The depth of theslot 235 is such as to terminate within the bore of the outer sleeve230; that is, the slot 235 extends into the bore of the sleeve 230.Unlike the openings 220 of the inner core 210, which are generallystraight, the slot 235 formed in the outer sleeve 230 is substantiallyS-shaped or curved along the circumference of the outer sleeve 230, asis best illustrated in FIG. 21. The preferred slot 235 is configured sothat when the inner core 210 is received within the outer sleeve 230,only one seed 3 in any of the seed channels 212 a, 212 b, 212 c, 212 dmay be visible through a conduit opening 220 of the inner core 210 inalignment with the slot 235 of the outer sleeve 230. This configuration,therefore, effectively shields personnel from exposure to the seeds 3contained in the seed cartridge 200.

While the inner core 210 preferably includes four substantially parallelseed conduits 212 a, 212 b, 212 c and 212 d, it is understood that thepresent invention is not limited to this number of conduits. Forinstance, the inner core 210 may only include three substantiallyparallel seed conduits 212 a, 212 b, 212 c so that the outer sleeve 230may be rotated relative the inner core 210, or vice versa, to a neutralposition where the slot 235 does not intersect with any conduit opening220 in the inner core 210. Thus, in this neutral position, no seeds 3, 3a, . . . , 3 n within seed conduits 212 a, 212 b, 212 c are visiblethrough the opening 220 and slot 235, thereby minimizing or preventingradiation exposure from the seeds.

A proximal end cap 240 is releasably secured or otherwise connected tothe proximal end 232 of the outer core 210 and a distal end cap 241 isreleasably secured or otherwise connected to the distal end 215 of theinner core 210. This is preferably accomplished after the inner core 210is received within the bore of the outer sleeve 230. The end caps 240,241 are generally cylindrical in shape and a preferred method ofsecuring the end caps 240, 241 to the outer sleeve 230 and inner core210, respectively, is by forming threads on the end caps 240, 241 forthreadedly engaging mating threads formed on the outer sleeve 230 andinner core 210.

Like the outer sleeve, the end caps 240, 241 are preferably made fromlead or steel in order to effectively shield personnel handling the seedcartridge 200 from radioactive exposure to the seeds 3 containedtherein. Alternatively, a lead foil may be inserted between each end cap240, 241 and the inner core 210, which foil may be penetrated by a pushrod or other device 250 (FIG. 28) in order to discharge seeds 3, 3 a, .. . , 3 n out of the BISC seed cartridge 200.

The proximal end cap 240 includes at least one cut-out section 245passing therethrough so that when the end cap 240 is secured to theouter sleeve 230 containing the inner core 210, the cut-out 245 is inaligned relationship with the particular seed conduit 212 a, 212 b, 212c, 212 d of the inner core 210 that is proximate the slot 235 of theouter sleeve 230, as well as that portion of the slot 235 proximate theproximal end 232 of the outer sleeve 230.

Similarly, the distal end cap 241 includes a plurality of apertures 246formed therein. When the distal end cap 241 is secured to the inner core210, each aperture 246 is in aligned relationship with one of the seedreservoirs 212 a, 212 b, 212 c, 212 d and the opening 220 associatedwith that particular seed conduit of the inner core 210. The sameoverall configuration of each aperture 246 is generally the same as theseed conduit 212 and corresponding opening 220. The seed cartridge 200is assembled by inserting the inner core 210 (containing seeds 3, 3 a, .. . , 3 n) within the outer sleeve 230 and securing the end caps 240,241 to the proximal end 232 of the outer sleeve and distal end 215 ofthe inner core, respectively. The assembled BISC seed cartridge 200 maythen be operably connected to the FOGISMA device 1 by aligning thedistal end cap 241 with the seed insertion port 81 formed in the housing20 of the device 1. The seed insertion port 81 preferably extendsthrough the housing 20 from the proximal end 15 of the device 1 and iscollinear with the seed alignment channel 62 formed in the elongatedmember 60.

A relieved portion or keyhole 82 is preferably formed in the proximalend 15 proximate the seed insertion port 81 for receiving a locking key242 formed on the distal end cap 241. The locking key 242 projectsoutwardly from the circumference of the end cap 241 and is receivedwithin the relieved portion 82 to operatively connect the assembled seedcartridge 200 to the FOGISMA device 1. Once key 242 is received withinthe keyhole 82, the seed cartridge 200 is rotated slightly to releasablylock the key 242 within keyhole 82. The opposite rotation of the seedcartridge 200 back to its original inserted position will release theseed cartridge 200 from the device 1.

When the seed cartridge 200 is releasably locked to the FOGISMA device1, one of the seed channels 212, apertures 245, insertion port 81 andthe seed alignment channel 62 are in aligned relationship (i.e.,collinear). In this manner, an elongated seed advancement push rod 250may be inserted longitudinally through the cut-out 245 of proximal endcap 240 and into the seed conduit 212 aligned with the cut-out 245. Atab 251 projects upwardly from the push rod 250 and extends through theopening 220 associated with the seed conduit 212 in which the push rod250 is received. The tab 251 also extends through the S-shaped slot 235of the outer sleeve 230.

Thus, seeds 3, 3 a, . . . , 3 n contained within a particular seedconduit 212 of the inner core 210 may be advanced or loaded into theFOGISMA device 1 in the following manner. After the assembled BISC seedcartridge 200 is operably connected to the device 1 (e.g., via lockingkey 242) the push rod 250 is inserted longitudinally through the cut-out245 of proximal end cap 240 and at least partially into the seed conduit212 aligned with the aperture 245. The surgeon or operator of the device1 is able to move the push rod 250 longitudinally through the seedconduit 212 toward the FOGISMA device 1 by grasping the push rod tab 251extending through opening 220 and S-shaped slot 235. As the tab 251advances distally through the S-shaped slot 235 of the outer sleeve 230,the outer sleeve is rotated relative the inner core 210 due to theS-shaped configuration of the slot 235 so that only one seed containedwithin the channel 212 bearing the push rod 250 is visually exposedthrough the opening 220 of the inner core 210 and slot 235 of the outersleeve 230. Such continued distal movement of the push rod 250 throughthe seed conduit 212 causes seeds 3, 3 a, . . . , 3 n to advance inend-to-end aligned relation through aperture 245 in end cap 241 out ofthe seed cartridge 200, through the seed insertion port 81, and into theseed alignment channel 62 of the FOGISMA device 1.

The capability of the seed cartridge 200 to expose only one seed at atime through the opening 220 of the inner core 210 and slot 235 of theouter sleeve 230 minimizes exposure of the surgeon or operator handlingthe seed cartridge 200 to the seeds 3, 3 a, . . . , 3 n containedtherein. In addition, such exposure of only one seed at a time permitsthe surgeon or operator to survey, inspect or otherwise measure thephysical condition and characteristics (e.g., chemical or radioactivestrength) of each seed contained within the seed cartridge 200.

Once the seeds 3, 3 a, . . . , 3 n are ejected from the BISC seedcartridge 200 into the seed alignment channel 62, the push rod 250 maybe removed from the seed cartridge 200 and the seed cartridge may beremoved from the FOGISMA device 1 by rotating the locking key 242projecting from the distal end cap 241 relative the keyhole 82 of thehousing 20 to disengage the key 242.

If a greater number of seeds 3 are still required for the particularmedical procedure, then the surgeon or operator of the device 1 mayrotate the outer sleeve 230 relative the inner sleeve 210 to align a newseed conduit 212 b (containing seeds 3) with S-shaped slot 235 of theouter sleeve 230. The seed cartridge 200 may then be lockingly securedto the device 1 in the manner described above so that the new seedconduit 212 b is in aligned relation to the seed insertion port 81 andseed alignment channel 62 of the FOGISMA device 1. The push rod 250would then be inserted within and advanced through the new seed conduit212 b in the manner described above. Additional seed conduits 212 c, 212d, etc. may be used in the above-described manner for insertion of aneven greater number of aligned seeds 3. It is understood that theFOGISMA device 1 may be provided with more than one keyholes 82 and/orlocking key 242 so that additional seed conduits 212 of the seedcartridge may be aligned with the seed insertion port 81.

Once all of the seeds 3, 3 a, . . . , 3 n are loaded in end-to-endaligned relation into the FOGISMA device 1, the BISC seed cartridge 200is removed from the device and the seed biasing member 70 (describedabove) is inserted into the seed insertion port 81 to bias the seedswithin the seed alignment channel 62 toward the multichamber seedtransfer barrel 45.

Referring now to FIGS. 24-28, another embodiment of the BISC seedcartridge 300 is illustrated having a generally cylindrically-shapedinner core or seed cassette 310 having multiple chambers or conduits 312extending longitudinally therethrough. The inner core 310 is preferablymade of either plastic or metal, and includes a plurality ofsubstantially parallel seed conduits 312 extending longitudinally fromend to end.

Each conduit 312 is generally slightly larger than the diameter of theseeds 3, 3 a, . . . 3 n for receiving the seeds in end-to-end alignedrelation. While the length of the inner core 310 dictates the number ofseeds that may be held in each seed conduit 312, each conduit 312preferably holds between approximately 25-30 seeds, 3, 3 a, . . . , 3 nin end-to-end aligned relation.

For each seed conduit 312, a longitudinal slot or opening 320 is formedin the circumference of the inner core 310, which opening 320 extendsfrom end to end of the inner core 310. Each opening 320 is tangential toone of the seed conduits 312 so that each seed conduit is open orslotted about the circumference of the inner core 310. While the innercore 310 preferably includes four substantially parallel seed conduits312, it is understood that the present invention is not limited to thisnumber of conduits.

The inner core 310 is contained within a cylindrically-shaped outersleeve 330. The outer sleeve 330 includes a bore extendinglongitudinally from the proximal end 332 of the outer sleeve 330 to thedistal end 333 of the outer sleeve. The diameter of the bore through theouter sleeve 330 is preferably slightly larger than the outside diameterof the inner core 310 so that the inner core 310 may be received withinthe bore of the outer sleeve 330. It is understood that the inner core310 and the outer sleeve 330 may be integrally formed as one piece.

The outer sleeve 330 is preferably made from lead or steel in order toeffectively shield personnel handling the seed cartridge 300 fromradioactive exposure to the seeds 3 contained therein. It is understood,however, that other materials such as plastic may be utilized in makingthe outer sleeve 330 and that a protective insulating layer of lead orsteel may be applied or bonded to the outer sleeve 330 to provide thedesired protection from radiation exposure.

The outer sleeve 330 has a circumferential slot 335 extendinglongitudinally from the proximal end 332 to the distal end 333 of thesleeve. The depth of the slot 335 is such as to terminate within thebore of the outer sleeve 330; that is, the slot 335 extends into thebore of the sleeve 330. Unlike the S-shaped slot 235 of thepreviously-described embodiment of the seed cartridge 200, the slot 335formed in the outer sleeve 330 is substantially straight along thecircumference of the outer sleeve 230, as is best illustrated in FIGS.22, 26 and 27.

The outer sleeve 330 is longer than the inner core 310 so that a portionof the interior of the outer sleeve 330 proximate the distal end 333thereof is substantially open when the inner core 310 is inserted orformed within the bore of the outer sleeve 330. A plurality of spacedapart locking keys 342 are formed proximate the distal end 333 of theouter sleeve 330 and project inwardly into the bore thereof.

An alignment adaptor/seed repository 301 is utilized to operativelyconnect the outer sleeve/inner core assembly 310, 330 to the FOGISMAdevice 1. The adaptor 301 is generally cylindrical in shape with a boreextending therethrough. The alignment adaptor 301 has a raised shoulder302 proximate the distal end 303 of the adaptor 301. The raised shoulder302 is received within the seed insertion port 81 formed in the proximalend 15 of housing 20 and is connected thereto in a conventional manner(e.g., threaded engagement). When installed, the bore through theadaptor 301 is in aligned relation (e.g., collinear) to the seedalignment channel 62 of the FOGISMA device 1.

Preferably, the BISC seed cartridge 300 will be provided to the surgeonor operator of the FOGISMA device 1 pre-loaded with seeds 3, 3 a, . . ., 3 n. At that time, the alignment adaptor/seed repository 301 may bereleasably connected to the outer sleeve 330 in order to seal orotherwise plug the inner core/outer sheath assembly 310, 330 prior touse of the seeds. Furthermore, as is discussed further below, thealignment adaptor/seed repository 301 may also be used to store unusedseeds following termination of the brachytherapy procedure. First andsecond film dams 317, 359 may be utilized to seal the inner core/outersleeve assembly and to maintain a sterile environment for the seeds.

Referring to FIGS. 23 and 24, a plurality of spaced apart grooves orslide locks 305 are formed on the circumference of the adaptor 301 andextend longitudinally from approximately the raised shoulder 302 to theproximal end 304 of the adaptor 301. The grooves 305 are spaced apartalong the circumference of the adaptor 301 so that each groove isaligned with one of the locking keys 342 formed on the outer sleeve 330when the outer sleeve is slid onto the alignment adaptor 301. A notchedor locking portion 305 a of each groove 305 extends tangentially alongthe circumference of the adaptor at approximately 90° to the groove 305.As such, the outer sleeve 330 may be slid onto the alignment adaptor 301by aligning and inserting the keys 342 within the grooves 305.Rotational or twist lock action of the outer sleeve 330 relative theadaptor 301 causes the keys 342 to lockingly engage the notched portions305 a. Similarly, rotation of the outer sleeve in the opposing directiondisengages the keys 342 from notched portions 305 so that the outersleeve 330 may be removed from the alignment adaptor 301.

When the seed cartridge 300 is releasably locked to the FOGISMA device 1via the alignment adaptor 301, one of the seed channels 312 is inaligned relation (i.e., collinear) with the bore through the adaptor301, the insertion port 81 and the seed alignment channel 62. In thismanner, an elongated, hollow push rod 350 may be inserted longitudinallythrough the proximal end of the outer sleeve 330 and into the seedconduit 312 aligned with insertion port 81 and seed alignment channel62. The seeds 3, 3 a, . . . , 3 n contained within that aligned conduit312 are received within the hollow push rod 350. A first film dam 359acts as a barrier to keep the seeds 3, 3 a, . . . , 3 n in end-to-endaligned position. A film bayonet 323 located within the seed alignmentchannel 62 may be used to tear or otherwise rupture the first film dam359, thereby permitting the seeds, 3, 3 a, . . . , 3 n to thereafter beejected from the hollow push rod 350, as is illustrated in FIGS. 30, 31Aand 31B.

Referring to FIG. 28, an elongated push rod or plunger 250 may beinserted through the hollow push rod 350 to advance the seeds, 3, 3 a, .. . , 3 n contained therein out of the seed cartridge 300 and into theFOGISMA device 1. First and second tabs, 351, 251 project upwardly fromthe hollow push rod 350 and seed plunger 360, respectively, each tabextending through the opening 320 associated with the seed conduit 312in which the hollow push rod 350 and plunger 250 are received, as wellas through the slot 335 of the outer sleeve 330. The tabs 351, 251permit the surgeon or operator of the device 1 to grip and advance thepush rod 350 or seed plunger 250 through the seed cartridge 300.

Thus, seeds 3, 3 a, . . . , 3 n contained within a particular seedconduit 312 of the inner core 310 may be advanced or loaded into theFOGISMA device 1 in the following manner as illustrated in FIGS.29A-29H. In FIGS. 29A and 29B, a full pre-loaded seed cartridge 300 isoperatively connected to the FOGISMA device 1 via the alignment adaptor301 by the twist lock action described above.

Referring to FIG. 29C, after the assembled BISC seed cartridge 300 isoperably connected to the device 1 (e.g., via alignment adaptor 301),the hollow push rod 350 is inserted longitudinally through the proximalend of the outer sleeve 330 and at least partially into the seed conduit312 aligned with the insertion port 81 and alignment channel 62. Thesurgeon or operator of the device 1 is able to move the hollow push rod350 longitudinally through the seed conduit 312 toward the FOGISMAdevice 1 by grasping the push rod tab 351 extending through opening 320and slot 335. As the tab 351 advances distally, seeds 3, 3 a, . . . , 3n advance in end-to-end aligned relation out of the seed cartridge 300,through the seed insertion port 81, and into the seed alignment channel62 of the FOGISMA device 1.

The seed plunger or push rod 250 is then introduced through the secondfilm dam 317 into the seed conduit 312 aligned with the insertion port81 and alignment channel 62, as illustrated in FIG. 29D. The surgeon oroperator of the device 1 is able to move the plunger 250 longitudinallythrough the seed conduit 312 toward the FOGISMA device 1 by grasping thepush rod tab 251 extending through opening 320 and slot 335, asillustrated in FIG. 29E. In this position, the aligned seeds 3, 3 a, . .. , 3 n are longitudinally advanced through the seed alignment channel62 toward the multichamber seed transfer barrel 45.

In FIG. 29F, the outer sleeve and inner core assembly is then disengagedfrom the adaptor 300 by removing the seed plunger 250, pulling back thehollow push rod 350 and rotating the outer sleeve 350 relative theadaptor 301 to release the slide lock. In FIG. 29G, the outer sleeve andinner core assembly has been removed from the adaptor 301 and the seedbiasing mechanism 360 is inserted into the alignment adaptor 301,through the seed insertion port 81 and within the seed alignment channel62 to bias the seeds 3 toward the seed transfer barrel 45.

Once in place, a seed biasing mechanism 360 may be locked to the adaptor301 in a manner similar to that described above with respect to seedbiasing mechanism 70, and the FOGISMA device 1 is then fully loaded andready to fire, as illustrated in FIG. 29H. Referring to FIGS. 32 and32A, the seed biasing member 360 preferably comprises an elongatedhollow body 361 that is closed on one end by a locking cap 362. Anelongated piston 363 is slidingly received within the hollow body 361and projects longitudinally through an opening in the distal end of thehollow body 361. A biasing member 364, such as a compression spring, ispositioned within the hollow body 361 and biases the piston 363 awayfrom the locking cap 362. In this manner, the seed biasing mechanism 360biases the loaded seeds within the seed alignment channel 62 toward themultichamber seed transfer barrel 45.

It is understood that once the seeds 3, 3 a, . . . , 3 n are ejectedfrom the BISC seed cartridge 300 into the seed alignment channel 62, theouter sleeve and inner core assembly 310, 330 may be removed from thedevice 1 and, if a greater number of seeds 3 are still required for theparticular medical procedure, then the surgeon or operator of the device1 may rotate the outer sleeve 330 to align a new seed conduit 312(containing seeds 3) with the seed insertion port 81. The innercore/outer sleeve assembly may then be lockingly secured to the device 1in the manner described above so that the new seed conduit 312 is inaligned relation to the seed insertion port 81 and seed alignmentchannel 62 of the FOGISMA device 1. The seeds 3, 3 a, . . . , 3 ncontained in the newly aligned seed conduit 312 may be loaded into theFOGISMA device in the manner described above.

After the brachytherapy procedure has been completed, the physician oroperator of the FOGISMA device 1 may discharge any unused seeds 3remaining within the device 1 into the alignment adaptor/seed repository301 of the BISC seed cartridge 300. FIG. 25 illustrates a longitudinalcross-sectional view of the seed repository 301 filled with unused seeds3 that have been fired into it from the FOGISMA device 1 in preparationfor their return to the seed distributor. This may be accomplished byfirst removing the alignment adaptor/seed repository 301 from the device1 and thereafter firing the unused seeds 3 within the FOGISMA device 1through a diaphragm 325 in the repository 301 that functions to keep theunused seeds 3 from spilling out of the seed repository 301.

Accordingly, a preloaded, self-contained BISC seed cartridge 200, 300 isprovided for brachytherapy operators and adaptable for use with a hostof implant applicators, including the FOGISMA device 1. The seedcartridge 200, 300 includes a protective outer sleeve 230, 330 forstoring a pre-sterilized inner core 210, 310 containing the seeds 3. Theeasy-lock and unloading of the BISC seed cartridge 200, 300 facilitatesimplantation by: (1) preventing radioactive exposure to staff before thebrachytherapy procedure; (2) ensuring a verified seed count; (3)eliminating the potential for seed spills or inadvertent loss due toseed manipulation in the brachytherapy hot room or operating suite; (4)efficient use of surgeon and operating room time by eliminating the needfor autoclaving of the seeds/cartridge before use in the operatingsuite; (5) allowing rapid deposition of seeds, which are preloaded withmany more seeds per cartridge than the standard number allowed byconventional seed magazines; and (6) limiting the potential for seedjamming or other misapplication through smooth mechanical action of seedloading cartridge.

FIGS. 33A-33E are illustrative of some of brachytherapy procedures thatmay be accomplished using the FOGISMA device 1 in accordance with thepresent invention. FIG. 33A illustrates use of the device 1 for prostatebrachytherapy using a minimal incision or no incision. An ultrasoundtransducer is also illustrated to assist the surgeon with the procedure.

FIG. 33B also illustrates use of the FOGISMA device 1 for prostatebrachytherapy using a minimal incision or no incision. However, unlikethe preceding example, a conventional X-Y targeting grid may also beutilized to assist the surgeon in properly locating the FOGISMA device 1relative to the implantation site.

FIGS. 33C and 33D illustrate use of the FOGISMA device 1 for a minimallyinvasive brachytherapy treatment associated with lung cancer. Similarly,FIG. 33E illustrates use of the device 1 for a minimally invasivebrachytherapy treatment associated with cervical cancer. An ultrasoundtransducer is also illustrated to assist the surgeon with the procedure.

The data presented below accentuates the need for the present invention.In 1995, it was estimated that 24,000 cases of pancreatic cancer wouldbe diagnosed and at least that number of patients would die of thedisease. Ten to fifteen percent of all patients (approximately 3,000)are treated surgically. For those patients having a tumor at thesurgical margins, brachytherapy could be used intraoperatively. Theother two-thirds of the cases (approximately 16,000 patients) wereinoperable at the time of presentation and would typically be referredfor radiotherapy following establishment of a tissue diagnosis.Previously, open biopsy and simultaneous seed implantation wereperformed on selected cases and the results in small series with theopen implant procedure were encouraging. With the advent of CT-guidedneedle biopsies virtually replacing open incisional biopsies, a needexists for a non-invasive or minimally invasive surgical implantationdevice such as that in accordance with the present invention that wouldallow simultaneous CT-guided needle biopsy and implantation of thetumor.

In addition, more than 50% of the 200,000 patients having GImalignancies develop liver metastases, in addition to the 18,500 peryear who are diagnosed with primary hepatobiliary tumors. In somecircumstances, patients with solitary liver lesions may be candidatesfor surgical resection. However, in instances where the patient ismedically unfit for laparotomy, or a lesion is technically unresectable,a non-invasive or minimally invasive surgical implantation device suchas that is accordance with the present invention for interstitialbrachytherapy would be desirable. The same principles may be applied topatients having a finite number of intrahepatic lesions, with lesspotential for uncontrolled bleeding in comparison to resection.

Furthermore, despite the fact that cervical cancer is the number onecause of cancer death in women worldwide, the advent of the Pap smearhas cut the annual incidence in the U.S. to approximately 15,000patients. Fully half of those patients with advanced disease(approximately 4,000 women) will fail radiation treatment. Many developpelvic intraperitoneal recurrences that may be exceedingly difficult toresect if surgery is attempted. Laparoscopic exploration andtransabdominal brachytherapy implantation using a non-invasive orminimally invasive surgical implantation device such as that inaccordance with the present invention would be desirable for salvage inthese patients.

Also, it was estimated in 1995 that there were 170,000 lung cancersdiagnosed in the U.S., with only 5% of those diagnosed patientssurviving five years. There are 34,000 cases of small cell lung cancerthat are usually treated with chemotherapy. Of the 136,000 non-smallcell cancer patients, approximately 40,000 are surgically resected. Theremainder of the non-small cell cancer patients (approximately 96,000)require irradiation. Overall, more than 50% of patients (more thanapproximately 67,500) treated surgically or with radiation die from theeffects of their intrathoracic disease. Reoperation for recurrence aftersurgery is seldom (if ever) performed. Reirradiation with external beamtherapy of recurrent disease in the chest carries many risks, includingfurther exposure of the spinal cord to doses possibly exceedingtolerance levels and inclusion of portions of precious remainingfunctional lung in the treatment fields. Transthoracic implantationusing a non-invasive or minimally invasive surgical implantation devicesuch as that in accordance with the present invention is a desirableoption for salvage in the more than 67,500 patients with recurrences andshould be explored as a means of boosting the dose of radiation in the96,000 patients who receive radiotherapy as their initial treatment,with the overall applicability exceeding 100,000 cases per year.

Furthermore, it was also estimated that more than 50,000 urinary bladdercancers would be diagnosed in 1995. Although the disease is localized tothe bladder in 90% of patients, as many as 80% develop recurrences.Cystoscopy and/or laparoscopy-guided interstitial implantation using anon-invasive or minimally invasive surgical implantation device such asthat in accordance with the present invention is desirable for thosepatients with muscle-invasion disease. The precedent for successfulbrachytherapy in bladder cancer was set by Dutch investigators whoplaced needles into the bladder and surrounding tissue throughlaparotomy incisions. However, various problems, including the need toreopen some patients to extricate stuck needles and impaired woundhealing, led to the virtual abandonment of brachytherapy in this organ.A non-invasive or minimally invasive surgical implantation device suchas that in accordance with the present invention is desirable option forthe radiotherapy and urologic communities, eliminating the problemsencountered by users of the older implantation technique whileduplicating its successful results in a patient population approaching36,000 per year.

Additionally, the therapeutic approach to organ-confined prostate cancerremains controversial. It was estimated that 250,000 men would bediagnosed with this disease in 1995, many via the PSA blood test. As aresult of the many advances in transrectal ultrasound, radioisotopeavailability, and computer modelling of dose distribution of implantedseeds, prostate implants have again become popular. They were initiallyaccomplished through a laparotomy incision using a retropubic approachbeginning in the early 1970's, but were abandoned because technicallimitations prevented consistency in implanting seeds in an effectivepattern. Nowadays, prostate implants have reemerged as an acceptedmodality with superb results. They are performed via the transperinealroute, though conventional instrumentation is primitive by today'sstandards. It is estimated that there are approximately 200 centersperforming more than 2,000 prostate implants per year. It must berecognized that, in this era of cost containment, prostate brachytherapyoffers the most rapid, least morbid, least expensive, and possibly mosteffective method of treatment for early stage cancer, i.e. 40% of allpatients (100,000). A safe, precise and convenient non-invasive orminimally invasive surgical implantation device such as that inaccordance with the present invention for brachytherapy is desirable fortreatment of these patients. Such treatment would represent a 5,000%nationwide increase in prostate brachytherapy, thus thrusting prostatebrachytherapy into the lead in the therapy of early prostate cancer.

The American Brachytherapy Society membership represents radiationoncologists who have a dedicated interest in implantable radionuclidesfor cancer control. Results of its survey of brachytherapy facilitiespublished in 1994 show that, among 1,321 radiation oncology centersnationwide, 78% of those responding perform some brachytherapy.Fifty-one percent of responding centers practice interstitialbrachytherapy.

The indications for utilization of a manual interstitial brachytherapysystem wedded to the latest technology in laparoscopic guidance inaccordance with the present invention are seemingly boundless. This is atechnology having broad applications and unlimited therapeutic benefits.In addition to the organ systems mentioned above, some or all aspects ofthis technology may be applicable to tumors of the upper aerodigestivetract, rectum, ovary, kidney, and brain.

Although illustrative preferred embodiments have been described hereinin detail, it should be noted and will be appreciated by those skilledin the art that numerous variations may be made within the scope of thisinvention without departing from the principle of this invention andwithout sacrificing its chief advantages. The terms and expressions havebeen used herein as terms of description and not terms of limitation.There is no intention to use the terms or expressions to exclude anyequivalents of features shown and described or portions thereof and thisinvention should be defined in accordance with the claims which follow.

We claim:
 1. A method for loading and discharging a plurality of seedsfrom an implantation device, comprising the steps of: loading the seedsinto the implantation device; selectively positioning one of the seedsin aligned relation to and communication with a bore through a hollowimplantation needle operatively connected to the device; selectivelymoving an elongated plunger from a retracted position spaced apart fromthe needle to an extended position to advance the aligned seed throughthe needle bore and out of the needle; and viewing the aligned seedprior to advancement through the needle and following discharge of thealigned seed out of the needle using an optical device carried by theimplantation device to provide visual assistance to the operator of theimplantation device to guide and verify implantation of the dischargedseed into a target area of a patient, wherein the optical device isoperatively connected to and carried by the plunger so that when theplunger is selectively moved to the extended position, the opticaldevice is carried by the plunger through the needle bore to a positionproximate the distal end of the needle.
 2. The method according to claim1, wherein the optical device is a fiberoptic scope.
 3. The methodaccording to claim 1, wherein the optical device is an optical scope. 4.The method according to claim 1, further comprising the step ofselectively moving an elongated outer sheath in predetermined incrementsrelative the needle to position the needle at the desired target area.5. The method according to claim 4, further comprising the steps of:receiving the seeds in aligned relation within a seed alignment channel;inserting one of the seeds located within the seed alignment channelinto a selectively movable seed chamber in aligned relation to andcommunication with the seed alignment channel; and selectively advancingthe seed channel containing the inserted seed to a firing position inaligned relation to and communication with the needle bore.
 6. Themethod according to claim 5, further comprising the step of selectivelymoving the elongated plunger from the extended position to the retractedposition prior to selectively advancing the seed channel.
 7. The methodaccording to claim 5, wherein the step of selectively advancing the seedchannel comprises the steps of: selectively moving a first advancing pintooth in a first direction into engagement with a first circumferentialcam portion formed on a seed transfer barrel in which the seed channelis formed to rotate the seed channel a first predetermined angulardistance; and selectively moving a second advancing pin tooth in asecond direction into engagement with a second circumferential camportion formed on the seed transfer barrel to rotate the seed channel asecond predetermined angular distance.
 8. The method according to claim5, further comprising the step of biasing the seeds aligned within theseed alignment channel toward the seed chamber.
 9. The method accordingto claim 5, wherein the step of loading the seeds into the implantationdevice comprises the step of: placing a plurality of seeds within a seedconduit formed within a cartridge; releasably connecting the seedcartridge to the implantation device so that the seed conduit is inaligned relation and communication with the seed alignment channel; andadvancing the seeds within the seed conduit out of the seed cartridgeand into the seed alignment channel of the implantation device.
 10. Themethod according to claim 9, wherein the step of advancing the seedwithin the seed conduit comprises the step of inserting a push rod intothe seed conduit to force the seeds contained therein out of the seedcartridge and into the seed alignment channel of the implantationdevice.
 11. The method according to claim 1, further comprising the stepof preventing the positioned seed from passing through the needle boreunless that positioned seed is being driven by the plunger as theplunger is selectively moved from the retracted position to the extendedposition.
 12. The method according to claim 1, further comprising thestep of providing a visual indication of the number of seeds ejectedfrom the implantation device through the needle.